What Causes White Substances Under Foreskin?

I am a 19yo white male.I am currently having 2 problems .#1 , I have a white substance under the foreskin of mt penis, it is like the head of my penis is peeling ( like skin after a sunburn )#2, there is a point on my foreskin that has gotten tight , it is like a rubber band, it causes pain when I peel the foreskin back recently I have been taking some anti-biotic pills for a bad cut on the back of my hand, I also was on a IV anti-biotic for 5 days for the same thing,