Burn wounds usually are caused by heatrocks, insufficiently covered heatmats, and by faulty-installed lighting.
At the time you discover a burn, it may be already too late to save the animal.

Treatment

Small blisters and burn wounds you can treat yourself by rinsing daily with Providone Iodine.
In doubt, or when the skin has been burned off and/or blisters have been ruptured, you may want to contact a veterinarian.

Burns do not only destroy the skin, but also the tissue underneath. This will cause the animal to lose fluids and will make it more sensitive to infection. The veterinarian will in many cases combine fluids and antibiotics, and will cut away pieces of dead skin and tissue to assure a faster healing process.
A daily treatment with a special antibiotic cream can be prescribed. This will also help to make the new skin stronger and to cast away dead tissue.

Author, Evert Henningheim

Bibliography:
Elliot R. Jacobson, DVM, PhD, DACZM (2003) Biology, Husbandry, and Medicine of the Green Iguana. Original edition., Krieger Publishing Company, Malabar, Florida, USA.
Source: Dr. Marja Kik, veterinarian for reptiles