Could juvederm cause an allergic reaction? I have very sensitive skin and have to be careful about the lotions I use, because a lot of them make my skin break out. What are the ingredients in juvederm? I want to make sure I don't have an allergic reaction

More probable. Yes, its prob the offending agent causing your problems, and the best way to find out is to stop, heal all areas, return to normal, and if you're game, use it again (if your reactions are mild). Thats the best real world test. Juvederm can cause allergies in those with allergies to certain proteins, like bacterial proteins.
Juvederm. There is the possibility of allergy and an allergic reaction when injected. Be sure to have your face evaluated by a board certified facial plastic surgeon and discuss the risks with your surgeon.
Juvaderm. Juvaderm is a soft-tissue filler used to restore tissue volume loss such as correcting wrinkling from aging. Its main ingredient is hyaluronic acid which is a naturally occurring glycosaminoglycan in our skin. So that its effect will last for 6 to 12 months and not just 2 to 3 days, it is chemically altered using butanediol diglycidyl ether so that it resists break down by our skin enzymes. The first hyaluronic acid fillers produced were made from rooster combs, but most filling agents are now made from the fermentation of streptococcus equi bacteria. Beyond the filling effect hyaluronic acids may smooth skin by stimulating collagen production in our skin (this has been suggested with another simular agent restylane). There is possibility of allergy to hyaluronic acid products (juvederm, Restylane (dermal fillers) and perlane) if a person has allergy to gram positive bacterial proteins. There is possibility of allergy to Hylaform if a person has allergy to avian proteins such as egg or feather. Some agents contain bovine collagen or other ingredients such as Lidocaine or botulinum toxin, so each would have to be evaluated separately for the possibility of allergy. The human-derived collagens should have reduced risk for allergenicity, but are not available in the us and could theoretically transmit infection. This is probably more information than you wanted but the bottom line is that: yes, allergy to juvederm is possible, and if this is suspected there are other options but all of them have potential for causing allergy!