See my post right above yours - one can do this yourself with the proper product. I've used the Tandy product a number of times, always with good results.While any snakeskin pattern product is gorgeous, unfortunately even with proper care they can age and lose their shine.
You could also have it restored by a professional. The restorer applies a clear glaze to the item and returns it to its original luster. I am not sure what it would be for a wallet but for a handbag it is pricy. However, if you really love the wallet, it will be well worth it.