Thanks for posting your query at DoctorSpring.com
I can understand your concern. I reviewed the picture.
It seems to be a bacterial infection called furuncle. However it's not easy to comment on a lump without examining it. I would recommend that you take an oral antibiotic like azithromycin for three days and apply Mupirocin cream twice a day for a week. You will need a prescription for the same.
In case it doesn't start improving in 3 days, it would be best to consult your dermatologist who can examine it thoroughly n opine.
Please let me know if you have any queries.