Thanks for the query.
Dont worry cancers are not sudden in appearance.
You might have developed furuncle
These are deep bacterial infections.
Treatment is with antibiotics.
Both oral as well as topical antibiotics can be used.
Please meet a dermatologist
for exact diagnosis.
Let me know if you have any other doubt.
you can ask a direct question to me on this forum, following the below link.
Wishing you a good health.