Skin irritation from Frontline

I put Frontline on one of my cats last Wednesday, and yesterday morning noticed that he'd lost all the fur on the site where I applied it.

I've used Frontline on him for many years - ie. 6-8. By the afternoon there was a scraped (looking) area, on part of the bare site, that was sensitive to touch. By last night, it looked like a scab starting to heal - a little yellow/pussy (but not wet) on the surface.

I know Frontline isn't comfortable for the cats, but this reaction isn't acceptable. Does anyone have any wisdom/suggestions to offer? Either something to place on the wound or alternatives to Frontline. (I need the tick protection, because we live in deer country.) My other two cats haven't had this experience - thank goodness - and they all have sensitive skin & get Derma-caps in their food.

TIA,

Liz