In reply to Reach>Talent: If it's really bad, hold it open with something (or if the hole is tiny, make a small incision enlarging it just enough for access and proper drainage it), then clean thoroughly by irrigating with iodine solution (mix warm water, salt and iodine tincture)and simultaneously agitating any crud out of there with a stiff bristled toothbrush (ideally new, definitely clean), cover with an absorbent dressing and then wrap tightly...
I did this with several of the toes on my left foot whilst I was out in Africa, supplemented by a course of antibiotics (which are available freely and cheaply out there).
Of course, if I'd had the option, *I'd have found a doctor* and had them sort it...