Penis injury/STD?

Hi i am very concerned about my penis. I have been having alot of sex latelt with a girl and every time we have had sex we have been fine up untill 2 day ago we started to engage in sexual contact and whilst we had been grinding naked my penis started burning like crazy we then stopped and the burnig continued leavig abrasion looking marks on my penis head also its been 2 days bow and it seems the swelling has gone down byt my oenis feels a bit sesotove still aswell as its starting to shed some sort of skin and flaking please help!