I am 17 years old 1 week before I had just broken the seal of penis me I had taken my foreskin backwards and the head of penis is out now and after 2 days I masturbate and I had found something bubble like structure just under the head of my penis and it is increase little bit it is just under the head of penis and it is just like the bubble which we see when we got burnt it just like that soo plss plss plss Doctor help me out with this I am very worried it 3 days gone and it just like that plss plss help.