Um, how do you measure a boil, Toddy?
(I think I will keep an eye on it, othrwise do nothing)
It's more the level of inflammation.
Is it deep still, not really risen above the skin ? or is it flared up and the skin thinned and showing pus underneath ?
Honestly, if it's still small enough that it's just flaring, try to draw it. The body will want to heal, just encourage it along. The hot flannel provides relief and encourages the body to clear it up.
The NHS don't recommend draining one yourself, but one colleague was plagued with them and regularly dealt with them herself when we were working in the back of beyond and no GP to hand. Just disinfected the area and a needle, inserted it into the swollen yellow bit and gently encouraged the mess to drain. Seemed to work, just disinfected it again and slapped a plaster on it.
Eventually though the Doctor reckoned that she had staph aureus ? on her skin and gave her antibiotic nose drops. I have no idea why nose drops, but that's what she got. Haven't seen her in years, no idea if they recurred, I just mind the nose drop thing.
Carbolic soap was the stuff folks were advised to use when I was at school, but that's a looong time ago