Well, herpes sores wouldn't last this long - that would be a week, maybe 2, at the most.
A syphilis sore lasts 3 weeks.
It could be something bacterial like staph or MRSA, that you'll need an antibiotic for. Maybe it's infected hair follicles that keep getting irritated so they won't heal.
The only way to know is to get them checked out. It's been 5 months, and it's time. Ask them to culture them for bacteria so you'll know if you need an antibiotic, and what antibiotic you'll need.
Let us know what happens.