M.S.
My son was 3 years,4 months old before he potty trained. I tried PTing at your son's age and it became so frustrating for me that I just put him back in diapers and decided to try again in a few months/weeks.
When it did happen it was two things, undies only and he had to clean himself up...I supervised, but he did the work and wiping. And he finally discovered a pair of underwear he didn't want to get dirty. (Thomas and Spiderman kept getting pee and pooped on and it didn't bother him in the least)! His underwear with animals on them (frogs, alligators, turtles, lizards) he would cry if he even got them a little damp.
Good luck...I have been there and thought I would go crazy before it was over...it will happen!! {{{hugs}}}