Hi! My first thought was it could be the wheat. It may take a few days to clear out of her system.
DS2 had a reaction to Oatmeal and it took a few days to clear up his rash on his face.
Have you changed soaps, detergents, anything else that comes in contact with her skin at all?
How long has she been on the formula? I think it would be odd that she would just know be showing a sign to the formula.
I don't think teething would cause the bumpy skin on her legs and stuff. Does it look like goose bumps?
DS2 had this and it gets worse with certain foods. The doctor said it is cause KP -Keratosis Pilaris.
Since you have stopped wheat, if it clears up, then I would try wheat one more time to see if the rash comes back. If it does, you will for certain.
Good Luck, Wendy