White Hard Bump/Puss and other skin problems: Skin Cancer?

I am 19 years old and I have many white hard bumps under the skin of my arm. It doesn't hurt but it is slightly visible and much more visible when you press on it. I started to get these bumps about two-three years ago. I just noticed these bumps spread to my butt as well. When I squeeze my skin in some areas, white puss comes out of it. I also get scabs in my hair (since I was little, I always had a habit of picking at the scabs in my hair). And, since one year ago, I started seeing stuff on my right boob. I first had a black hard pimple like thing growing, but the stuff inside finally came out so it disappeared. However, now I get small/thin black pricks that pop up occasionally. I try to squeeze it out and eventually it comes out. I don't know if all of these relates, but I also have acne prone/dry (combination) skin. I am very scared that I have skin cancer. I will be seeing a dermatologist soon but if anyone knows what may be causing all these problems please let me know!

[Bhupinder Kaur, MD]

Hello,
From the symptoms it can be a sebaceous cyst. It is filled with a soft, whitish brown material that sometimes oozes out onto the skin's surface. This material is called sebum. Treatment includes small surgical opening into the skin and removing the sac (excision biopsy). But recurrence is quite common. I suggest you to get the diagnosis confirmed from a dermatologist after examination.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.