Hello and welcome to healthcaremagic
I would keep a possibility of Furuncle/boil, which is bacterial infection of the hair follicle. The infection usually gaining entry through the hair follicle. Usually the infection is confined to the skin and
soft tissue and may not enter the blood stream.
Underlying diabetes/raised blood sugar, if not well controlled can be a major predisposing factor for recurrent soft tissue bacterial infections.
Uncontrolled diabetes may also affect peripheral nerves, thus giving rise to sensory loss in the hands and feet which may be confused with leprosy, but it is not due to it.
I would suggest that you get him a fasting blood sugar levels as well as a pus culture and sensitivity test done.
The best way to approach is to start on an empirical oral antibiotic for a week OR 10 days (My choice of oral antibiotic would have been
Amoxycillin 500mg in combination with
clavulanic acid 125 mg, thrice daily, for a week OR
Cephalexin 500ng thrice daily OR
Cefadroxil 500mg twice daily, for a week). This would take care of the infection.
An OTC antibacterial cream/ointment e.g 2%
mupirocin can be applied twice daily.
An OTC pain killer e.g ibuprofen once or twice daily would help you deal with the pain.
regards