What are the chances of me having an allergic reaction to Juvederm, if I have previously reacted to Restylane?

Since Restylane® and JUVÉDERM® are both hyaluronic acid fillers, it is very possible that you could still have an allergic reaction when using JUVÉDERM. You could, however, try a different type of filler that doesn’t contain hyaluronic acid, such as RADIESSE®, Sculptra® or collagen injections. Just make sure you let your provider know about your previous allergic reaction to Resylane® so they can recommend the safest and most appropriate treatment for you. Good luck!

From your description of symptoms and their dynamics it appears you had a delayed hypersensitivity reaction. It typically begins days after injection and it may subside periodically. The most likely reason are the residual proteins or sugars contained in hyaluronic acid fillers and come for the process of making it through bacterial fermentation. There are other types of delayed reactions that form painful nodules and/or indurations. These type of reactions are impossible to predict and have been described while using different fillers, including Restylane line of products. Therefore, there is a possibility of the same type of reaction to Juvederm, even though the overall risks are minimal. One of the contraindications listed in the filler inserts is previous allergic reaction to hyaluronic acid fillers or history of multiple allergies.The alternatives to hyaluronic acid fillers depends on the availability of fillers in the area you live, e.g..  Ellanse,  Radiesse, Sculptra , and Allofill (fat derived) or fat transfer. Depending on the area of correction one could also consider implants. Good luck!