Permethrin-triforce-paresthesi…

We have a mini schnauzer who is 3 years old. We recently tried to switch from frontline to triforce pet. Almost immediately, she had a reaction to it.She started to whine and scratch. About 5 hours later, she had taken off patches of hair on her side, so we bathed her. After a rough night of her whining, constantly moving, and being unable to sleep, I called the vet. She recommended I try cortisone. On the fourth day, we called the firstaid hotline and was told she had paresthesia, and that it would last no more than three days. Well, today is the sixth day and she has developed white sores with what appears to be blood around it, so we are taking to the vet. Has anyone ever experienced this with their pet and what was the scernio/solution?