My chihuahua is developing gray spots on head and on sides of abdomen

[babyc769]

My chihuahua is developing gray spots on head and on sides of abdomen, I was wondering what she may have so I can treat it? I think she has allergies but I want to figure out what type. I took her to the vet and they gave her a shot and antibiotics which helped with her ear scabs but she still has the discoloration. She seems like she may have some anxiety as well. When I adopted her she had some scabs on her ears, she sheds a lot and her fur seems kind of rough to me not soft like my other chihuahua but the grey spots just started happening a couple months ago. Any help or advice would be greatly appreciated. I have spent several hundreds of dollars on vet visit, medicine and food. I just want to get my dog better. She doesn't seem sad and she is very loving and playful but I can tell something is wrong. oh! I forgot ne thing she chews on her feet a lot.