Thanks for your question on Health Care Magic.
I can understand your concern.
Possibility of
brain cancer is very very rare in your case because of your age.
Brain tumours are common in children less than 10 years and old age people more than 60 years.
So at your age of 19 years, no need to worry for brain tumour.
Possibility of benign tumours like lipoma or sebaceous cyst or
dermoid cyst is more in your case.
So better to get done clinical examination of swelling and
ultrasound examination of swelling for the diagnosis.
You may need surgical removal of the swelling.
Usually brain tumour causes
constant headache, vomiting, difficulty in vision,
unconsciousness etc. All these are absent in your case, so don't worry about brain tumour.
You are mostly having benign skin tumour.
Hope I have solved your query.
Wish you good health. Thanks.