Myrna's Paw Infection and Chlorhexidine

Myrna could have a compromised immune system due to her HCM or to any of the meds she's on.  I'll have to ask the cardiologist when I see her in July.  But Myrna has a slight infection on her front right paw. She needs to have chlorhexidine rubbed into it once a day and wear the collar while the med dries enough so that she can't lick it off. Not sure why she has an infection. She had been constantly cleaning it since late Monday which I thought nothing about until she drew blood Wed. Thursday we went to the vet and voila! Nothing inside pad; no rips only where she's picking at the pads. Could be allergies. Need to keep an eye on other pads. Is healing quickly.