Hives Not Likely from Dermal Fillers
The timing of the occurrence of hives is not likely to be the hyaluronic acid filler (e.g. Belotero). you received the Belotero 2 months prior to the injectable filler. If you had developed it immediately or within a day, one could have assumed they were related.
I agree with Dr. Emer that it is very very unlikely that the hives have anything to do with the filler injection and that the 2 events are merely coincidentally related. The hyaluronic acid component of the filler is shared by every species on the planet, so it is impossible to react against it. Sometimes residual products (chemicals) from the manufacturing process can lead to local effects in the skin, but even that is extremely rare.
Hives from Fillers
Hives are not generally a result of fillers injected especially months later. Hives are generally the result of a virus or an allergic reaction. Please consult a board certified dermatologist to find out the cause of the hives. You can also have skin tests to determine if you are allergic to specific dermal fillers.
Hives From Fillers
I do not think that filler injections would cause hives especially a month after injections. Most hives are idiopathic, meaning there is no known cause or it is due from a recent viral or bacteria infection like a cold or sinusitis. I suggest going to see a dermatologist for hive workup. Starting antihistamines or oral steroids would be helpful at this time. Best, Dr. Emer.