My dog spins, pants, and bites. What's wrong and what should I do?

That is not the type of reaction I would expect from a bug bite. I would be concerned about pain first and foremost. If she's still pacing, panting, or acting erratic, I would recommend taking her to a vet right away for evaluation. They will likely do a physical exam and take some x-rays, maybe run some blood work. I hope she's feeling better soon!

You have described an obsessive compulsive disorder (aka: stereotypy). You are not likely to change this behavior but you could always consult with a professional dog trainer if you wan to attempt to redirect the behavior which may help to minimize it. ( https://www.sfspca.org/sites/default/files/dog_behavior_repetitive-behavior.pdf )

There can be several possible causes of Riley's abnormal behaviors, including irritation from full anal glands, parasites or seizure activity. That said, if Riley is aware and responsive to you at all times, seizures seem less likely. Anal glands are scent glands that typically empty with a bowel movement, but sometimes they need to be manually emptied. If this continues, Riley should be seen by her vet to express/empty her anal glands and check a stool sample for the presence of parasites.

Any abrupt change in behavior without a known cause should be investigated by your vet as soon as possible. Sometimes this is the only sign we get of a medical condition. The behavior could be due to feeling ill, being in pain or may be because of a developing neurological condition. Your vet will do an exam, labwork and possibly some diagnostic imaging, x-rays or ultrasound to determine the cause for your pet's change in behavior and, based on the results, will be better able to advise you on treatment options.

She does need to see a vet as soon as you can as this sounds like a neurological problem. It may be a stroke, an inner ear infection, or vestibular disease. Your vet will examine her and start her on medicine to help with the dizziness and off balance so she can rest. Most regain normal function with time and treatment.

These can be symptoms of many serious medical issues, anxiety, fear, pain, neurologic disease, infection, etc. I would recommend that you have him checked out by a vet to see what could be going on. After a thorough physical exam and discussion of his recent history, the vet may recommend diagnostics, such as blood work, x-rays, ultrasound, etc. to diagnose the cause.

It sounds like your dog should be seen by a vet for a thorough examination to determine the cause. I am concerned that he looks like he is ready to pass out so please call your vet or go to an emergency clinic. It could be caused by pain, parasites, metabolic/endocrine disease, infection, etc. and your vet can do a workup to diagnose and then determine what treatment is needed.