I have ocd and can not stop feeling this one area of my breast. i'll poked so hard it's now bruised. does this make it likely i'll get breast cancer?

No: However if you are concerned about the possibility of developing breast cancer, even at your age, go see your Dr.

Harm from checking: Some checking compulsions can inadvertently cause harm. In your case this has taken the form of a bruise. Another feature of OCD is seeking reassurance and your question appears to be doing just that. This is another form of compulsion and you will not be helped by getting reassurance.

No ,it is highly unl: It is not so easy to create Cancer. Trauma certainly can not change our body cells that much, so it is highly unlikely that you have to worry about Cancer unless there is a growth or lump already present there. Sometime in the future you should get a mammogram(when you are near 40 years old) of this breast,just to be sure. But they would not like to do X-rays in younger women.(under 30 year old)