I’m so sorry to hear about your predicament. There are actually a number of things you can do; You should try taking oral supplements of Vitamin D (including Vit D3). If your skin is already so sensitive, I don’t think using self tanning products is a good idea for you.
Lamelle has a fantastic oral supplement that you can also take along with your Vit D. It is called Ovelle and it is predominantly a skin supplement containing a high concentration of Pycnogenol which is a potent anti-oxidant. Also make sure you are wearing a broad spectrum SPF that does not contain sensitizing ingredients, such as Skin Medica or Lamelle’s sunblocks. You can also take the oral supplement made by Heliocare, which is basically a oral sunblock, containing an ingredient called fernblock, which also protects the skin. If you are going to be spending some time in the sun for whatever reason, try to do so out of “peak time”, ie NOT between the hours of 11:00am and 3:00pm. I really hope this helps you.