Can Stretching To Much Foreskin Cause Harm?

I am embarrassed to say this, but i am very scared right now. When i was born i believe the doctor failed to do a perfect circumcision leaving me with too much skin covering the head of my penis. I also remember being to the try to stretch the skin as I got old the reveal it. Now... I am 15, and am unsure if I have done just that, or something terribly wrong. I have most definatly exposed the head of my penis, however the skin that i pulled back feels tight, and the head is becoming very cold, and purple as if i have cut off circulation. This is very very urgent