Hii ,
Welcome To HCM & Thanks For Asking Your Query Here
there are variety of causes which may lead to a lump on head and
scalp including from some common causes like sebaceous cyst ,
Dermoid cyst to some serious tumors and it needs care full physical examination as well as investigations to rule out exact medical condition
however if your lump is hard to firm in consistency. it may be a Dermoid cyst which are benign or non harmful lesions and they will not lead to any complications
if it is round in shape and is movable than most probably it is a Sebaceous cyst which are often harmless and cause no pain, they may require no treatment. They may also go away on their own
however Occasionally, a sebaceous cyst may become infected and may also need to removed surgically
i would strongly suggest you to visit your doctor , He will check it thoroughly and may want to perform a
biopsy to rule out whether it is a cyst or any suspicious growth(Tumor)
remember any serious tumor diagnosed early has very good prognosis and good possibilities are there for a successful treatment
I Hope it Helps
Get well Soon