That is a tough spot, right at or near the armpit like that ... because if it's really deep it can escape even hot compresses.

I would be flushing with something other than my wound care, which is more for superficial wounds and not deep wounds. Like squirting straight Betadine in there 3x/day.

A drug like cephalexin at 3x day, properly dosed, would be what I would use ... or Clavamox ... but that penicillin is useless for that.

A good rule of thumb is, anytime you don't see progress within 3 days, or if it gets worse, your antibiotic choice isn't working.

The compresses are still good, but I would be squirting straight Betadine in there, and I would upgrade my antibiotics immediately.

Good luck,

Jack