SAN JUAN, PUERTO RICO — It’s been more than three weeks since Hurricane Maria devastated Puerto Rico, but like so many islanders, Carmen Pantoja is still desperate for the basic necessities: food, water, medicine.

Her tired blue eyes filled with tears as she told The Post she can’t find medication for her son, Hector, who suffers from epilepsy and hydrocephalus, a buildup of fluid in the brain.

“There hasn’t been any help from the government, nobody has passed, nobody has come, nobody,” Pantoja, 69, said outside her home in Vega Baja, a small town in the forests of north-central Puerto Rico.

“And right now, nobody has come to visit, just one friend of mine came and brought some groceries.”

Pantoja and her 44-year-old son couldn’t leave their home for more than a week after Maria hit because the roads were blocked by debris.

She finally got to the local pharmacy this week — only to find they’d run out of medication.

“There’s no help yet since there’s no signal, we’re without communication,” she said Tuesday afternoon.

Pantoja is now struggling to collect enough rainwater to survive on.

“The neighbors … have put up signs [saying] that they’re the forgotten because over here nobody has appeared.”

Her daughter-in-law, 53-year-old Rosa Sanchez, agreed.

“Not even the mayor or the Red Cross, nobody has come to this area to ask if we need anything,” she said.

It’s clear Maria wrought catastrophic damage on the US territory — setting Puerto Rico back decades.

But the burning question in many residents’ minds remains: Where’s help from the government?

The Post spent three days traveling along the destructive path the eye of the storm took across the island, and only witnessed one instance of federal aid distribution.

Eighty-four percent of the island remains without power, and only 63 percent of residents have clean drinking water.

While thousands of containers of supplies have been brought to San Juan’s port, transporting those goods to Puerto Ricans in remote and mountainous areas has proven difficult — initially because roads and bridges were destroyed by the storm.

In San Juan, the Cheesecake Factory is delivering takeout to air-conditioned homes. In the interior of the island, residents aren’t sure where their next sip of water will come from.

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In the southeastern coast of the island, the eye of Maria first made landfall in a wetland reserve in Maunabo, where gray palm trees now bend to one side as if flattened by a bulldozer.

The turquoise Caribbean Sea still sparkles in the distance — but it’s hard to imagine when the area will be tourist-friendly again.

Abigail Sostre Garcia, 64, who lives on the edge of the wetland reserve, said she and her husband both have cancer — and can’t track down the medicine they need.

“I have now gone one week without any medication at all, the pharmacies aren’t open … There’s just no medicine left and I can’t really communicate with anybody on the outside,” Garcia said, standing on the porch of her peach-colored home.

“FEMA hasn’t come here yet,” she added.

Once an idyllic island paradise, with pristine beaches and towering royal palm trees, the southern coast of Puerto Rico now looks like something from an apocalyptic film.

“We’re now 21 days post-hurricane and I’ve only seen the municipality passing out water bottles and [ready-to-eat meals] once,” said Angel Ortiz, 50, pastor of Iglesia de Dios Pentecostal in Maunabo.

“[The government] brought us nine bottles of water, FEMA has said that they’re going to come but I don’t know if they actually have … the people here are really, really needy.”

In the town of Patillas, also along the southeastern coast of the island, Jorge Colon, 57, said Maria’s winds ripped off his bedroom wall and the roof of his family’s home, leaving it vulnerable to bats and mice, which have already moved in.

He’s hoping FEMA agents will arrive soon and find them a new place to stay.

“It’s a nightmare … we may have to leave here. I don’t know if they are going to give us a place to stay … I hope they provide us with a place to live, a home or something,” said Colon, wearing a dirty, white Old Navy shirt with a Puerto Rican flag on it and a Florida State University cap.

Moving farther west along Maria’s route through the La Cordillera Central mountain range, Betzeida Labron, 55, said the vicious storm blew away her wooden home, leaving behind nothing but a door mat and the tiled wall of a kitchen.

“I think it would be the best option to leave Puerto Rico because this is just too strong, I don’t have the strength to confront it,” she said through tears, adding that she hasn’t received any government help since the hurricane hit.

In the center of the island, it’s easy to see where the eye was: Walls of trees along the mountains stand blackened, stripped of their lush leaves. Many roads are still cluttered with storm debris.

Carmen Perez Sierra, 64, who lives in the city of Aguas Buenas, said her entire home was destroyed. Her sister, who needs an oxygen tank, fled to her son’s place in New Jersey because she couldn’t get the medical care she needed on the island.

“After the storm there was no communication or anything. She spent a few days without oxygen but we solved the problem between the neighbors, we charged her [portable oxygen tank] with a neighbor’s generator,” Sierra explained.

“I haven’t received anything from the government,” she added.

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By the time Hurricane Maria made it to the northwestern coast of the island in Camuy, she’d lost much of her fervor, her winds reduced to Category 3 before she spun off into the ocean.

The last place she hit was a beach called El Peñon de la Cruz — where a wooden cross on top of a small, rocky island still stands, a symbol of the strength the Puerto Rican people have had to channel.

Daniel Batista, 49, walked onto the pier to get some fresh air and clear his head after being cooped up in his home since the storm.

“The government response … hasn’t been good … today is the 21st day after the hurricane and there are still people who haven’t received any type of help. There are people and families that not even the central government has gone to their houses,” Batista said.

“We were going through the worst moment in the history of Puerto Rico and this was the reality that was dealt to us.”