Hi there Esteban!
It does appear that you are describing a 'whitlow' or a 'Felon' or a 'simple abscess'.
Was there any prior injury
to the site that you can recall?
How old are you? Any Diabetes
concurrently or on any medications?
This has best got to be shown to a dermatosurgeon or a general surgeon
It may have arisen from some viral infection & or some minor trauma.
An antibiotic/antinflammatory agent is best taken in a dose suitable to your body weight & this will require a prescription from the surgeon or your local GP.
Locally, might i suggest using a 2% mupirocin
cream/ointment that will help quell the infection.
Wish you a speedy recovery & Good health always!
Dr Praveen Rodrigues MD
, Cosmetologist, Venereologist
Vikram Hospital, Bangalore, India