Sheena Upton ... aka Kerry Campbell ... aka Botox Mom ... tells TMZ she has undeniable proof that her story was scripted ... including photos that appeared to show Sheena injecting her 8-year-old daughter.
For the very first time since the scandal broke, Sheena is telling her side of the story -- explaining to TMZ how she first got in touch with the U.K. newspaper The Sun through a close family friend and was under the impression she was only doing a simple story about a spa day with her kid.
But Sheena says during the photo session -- producers asked her to pose with a medical syringe and "act like I was just holding it up."
She says she had no idea the story was going to be about Botox -- and claims she doesn't even know what Botox is.
After the photo session, Sheena says things began to spiral out of control -- and she received detailed scripts instructing her how to carry on the lie in front of television cameras.