I find that one of the most important aspects of resolving hot spots is to shave the affected area down to the skin, typically I use a #40 blade to achieve this. Removing the hair allows better oxygen circulation to the affected area and likely your vet will recommend clipping and cleaning the area. Its also important to use an e-collar to keep your pet from licking or chewing the area. In some cases, antibiotics (oral or topical) may be necessary to resolve the infection