Thanks for the query.
In tattooing needles are pierced and hence there is always a chance of infection.
You might have developed furunculosis
It is a deep bacterial infection.
The bacteria might have been driven deep with the infected needle.
Treatment with oral and topical antibiotics is required.
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.