Hello,
Dermaroller is used
for Stretch marks,
wrinkles, scars and uneven, pitted skin. It is not used
for bumps
on the chest which could be due to sebaceous cysts. 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 dermatologist. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.