Do I have Cancer?

I am a 17 year old female and for the past two(?) days, my left nipple has been itchy (but its on and off) and there is a patch of discolored skin on my left as well above my nipple. At first I thought it was a bruise, but I am not sure anymore because when I press it, it doesn't hurt and its more of a brownish yellow color than a purple blackish color. Could these be symptoms of cancer? I've Googled it but I would like more confirmation before I go bother my doctor.