Not sure what kind of skin problem my cat has

My cat has been licking herself a lot lately.  More than usual.  I decided to de-flea her since it has been awhile from her last one.  So I put some of the medicine on her shoulder blade which she reacted and ran away very fast as if something stung her.  Later on I saw that the area where I put the de-flea is inflammed.  There's a few red spots that looks like rash.  I am not sure if this is from ticks or some other skin condition.  I have attached a picture. Any suggestion is appreciated.'

What kind of flea stuff did you use?  Did you wash it off?  Some of what you get over the counter is toxic.

It's over the counter that I bought at Walmart. I've used it before but never had this problem.

I hope you washed it off!  Seriously, I have heard some terrible stories about over the counter stuff.  I hope your kitty is okay.  If not, you should call a vet.