EXCLUSIVE

Justin Bieber is worried about what cops are going to find on his cell phone, but we're told his issues involve nakedness and drugs ... not so much eggs.

Law enforcement sources tell us ... when they searched Justin's house Tuesday, they seized his cell phone ... took it right out of his hot little hands. Sources say cops are interested in texts that could incriminate him. Cops want to see if he texted someone after the fact and bragged about the egging. One law enforcement source called it a "text high 5."

Sources tell us ... he's concerned more about drug discussions and references. Even if cops find drug references, Justin's in the clear given there's no physical evidence -- nonetheless J.B. is afraid it will leak out.

We're told he's also concerned that there are naked photos in his phone, although we don't know if they're action shots, selfies, etc.