Best thing one can do for a hot spot is shave the area to allow air to get to it, and dab with witch hazel several times a day. Another strong recommendation is Bailey's Skin Rescue (
Canine Coach on Call).
Both Baron and Neelah had hot spots on their heads (Baron from a tick bite and Neelah from I don't know what!) - shaved the area, cleaned well and applied witch hazel twice a day. I think Neelah healed faster than Baron because she didn't scratch at it like he did, plus she's on antibiotics for a low grade UTI.
The Bailey's Skin Rescue product is AWESOME - I can't recommend it enough!