The woman who went on "Good Morning America," claiming she injected her 8-year-old daughter with Botox, now swears under oath ... she made the entire story up for a few hundred bucks.

TMZ has obtained a sworn declaration written by Sheena Upton, who claims she was recently approached by the British tabloid, The Sun, and asked "to play the role of Kerry Campbell" for a story called "I Give My 8-Year-Old Daughter Botox."

Upton now confesses The Sun paid her $200 adding, "I was provided with the story, instructions and a script to follow for a recorded interview."

After the story ran in The Sun, Upton says she was approached by "Good Morning America" and "Inside Edition" and claims she was offered "a large fee" to appear on camera. She went on both shows and re-told her story.

After the interview, child welfare officials took Upton's daughter away.

Upton now admits in her declaration, "The truth is I have never given my daughter Botox, nor allowed her to get any type of waxing, nor is she a beauty pageant contestant."

Upton says professionals agree with her declaration, because on May 17, she took her daughter to the UCLA Medical Center and says, "After my daughter received a full medical exam, the results indicated that she has not ever received treatments including Botox or other such injections."

We're told the UCLA reports were forwarded to child welfare officials, who then returned Upton's daughter to her, with the provison that a cousin would stay with her and the child for the time being.

As for "Good Morning America" -- sources connected with Upton claim she was promised $10,000 to appear. We do not know how much she was offered for "Inside Edition."

As for the declaration -- signed under penalty of perjury -- we're told Upton wrote it so her lawyer can secure full rights to custody of her daughter.

An ABC News insider tells TMZ, "There is no truth to the story about compensation, but they did pay a broker no more than $10,000 to license photos."

UPDATE 8:20 AM PT: An ABC News spokesman tells us, "We have just seen the sworn declaration on TMZ written by Sheena Upton, a.k.a. Kerry Campbell , and are vigorously investigating her most recent statement and rapidly shifting story."

The rep continues, "Good Morning America has repeatedly questioned Upton, members of her family, and other sources who again and again stood by the Botox story."