What Causes Red Dots On Penile Head After Masturbation?

Hi Doctor. Every time I masturbate I tend to get a red dots on the penis head that dont itch. I also get red blotches on the underside of my foreskin. After 2-3 days of hydrocortisone it seems to clear up. Could it simply be just the friction from masturbation or is it eczema? I used to have eczema when I was around 15 but it all cleared up. I also get eczema looking patches on my penis shaft after masturbation which also clears with the use of hydrocortisone. Could this be eczema because I do not get it anywhere else on my body?