i agree with cellulitus ! he needs antibiotics x x
Sounds like maybe something I had once,a brown recluse bite.That's how it started out when I got bit.I'd check for a small bite somewhere first.But that's infection I am positive of.You really do need to get him to the Dr soon as possible.
it sounds to me like your husband may have celluitis i have had this before and it is very painful he should go to the emergency room as this can be dangerous