My Guinea Pig Gabby has been scratching and biting at herself for 4 months now. She went to the vet here in town and got a shot of Ivermectin. It didn't help. So I took her to a different vet in a bigger city. He couldn't find any bald patches. He ruffled her hair up, put her on a white piece of paper, and shook her. Nothing showed up on the paper. He said for certain she didn't have fleas. But he gave her no treatment. The problem persisted. I read online that an Ivermectin shampoo might take care of the problem. So I went back to the vet here in town and asked for this. He said he wasn't a Guinea Pig expert but he would make the shampoo. Then he came back into the room and said he had something better than Ivermectin. He gave me a couple of doses of Imidaclapid. She got one dose. It didn't help. The vet here in town referred me to an exotic vet in a bigger city. So I took Gabby there. The vet looked through her hair and said she didn't have lice. The vet asked me if I was itchy. I was so I said yes. Strangely enough I got a servere case of Scabies right around the same time Gabby's problem began. My Scabies has since been eradicated. They're gone. Gabby's cage is in my bed. I sleep with her at night. Anyways, this Exotic vet suspected Sarcoptic mites or scabies on Gabby. She couldn't do a skin scrape because Gabby has no bald spots or visible sores. The doctor also said sometimes a skin scrape will make a Guinea Pig bleed. So she gave Gabby a dose of Revolution on the back of her neck. The vet gave me another dose to give her on September 8. About 3 weeks went by and I thought I saw that Gabby was not scratching although I may not have been watching her very closely. Then I started seeing Gabby biting herself and scratching again. I called the Exotic vet back and explained the situation to her nurse. The doctor said since it was close to the date the next dose was supposed to be given to go ahead and give it to Gabby. The nurse said to give that about a week and a half and if Gabby still didn't stop itching the doctor wanted to start allergy testing. I gave Gabby the last dose of Revolution yesterday. So far no change. Sometimes she will hop up like something is biting her. Sometimes she'll shake her head or body from side to side like she's trying to shake something off. Also a few times I saw white stuff like dandruff in her hair. Other than the scratching and biting herself, she is eating, drinking, and playing just like her old self. I gave her a little bit of children's Benadryl and it seemed to put her asleep for about 10 minutes and during this time she didn't scratch. But after the 10 minutes, she started scratching and biting herself again. She is scratching all over. Her body, her ears, her face. And she is biting her body and her legs. I am at my wit's end. It kills me to see her miserable like this. And I don't have too much more money to spend on this. Also the vet here in town said she looks perfectly healthy and her weight is normal too. Does anybody have any idea of what the trouble could be? Does anybody have any idea what to do? All help will be appreciated.