Foreskin is lot thicker on underside of penis– is this normal or bad? (M33)

M33

Male, 33 years

Hello. Been doing foreskin stretches as I have phimosis – I can’t see my penis in there at all.

Now I’m noticing that foreskin “above” the tip is way thinner than what’s “below” the tip are (and tip is way in there, especially as my soft penis is way smaller than erected one)

My question:

1. Is it normal that one area of foreskin, the below area, is way thicker?

2. I grew up not knowing a thing about masturbation or foreskins so when I discovered it as a kid, I did a lot of stuff for years, like rubbing through clothes or against stuff.

Could I have made foreskin thicker by rubbing it against penis head?