So I stupidly watched videos on YouTube of maggots feasting on people including a video of a man with maggots in his gums and now I am absolutely paranoid and terrified that maggots might enter my body and do the same. How can I get over this phobia?
Yeah, maggots don't like healthy tissue, they only eat diseased or rotted tissue. Some doctors have taken to using maggots raised in a sterile environment to remove dead and diseased tissue in cases of extreme infection and the like. The maggots eat the dead and dying tissue, leaving the healthy tissue to heal. So unless you have a major infection somewhere, I think you're safe.
Watch something that makes you happy not fearful!
Recognize the fact that silk worms and maggots only eat dead tissue, so they won't eat your living body. If that fails, see a therapist.