Wow, a couple of weeks, that isn't good. Check your temps, make sure you have a gradient...70's cool side up to 90* warm side. Make sure he/she has a humid hide in each side (cool & warm). I would turn the light off unless it is the only heat source you have. Put his tank in an area that is not disturbed or "busy". If you can find a petstore or bait shop that sells waxworms, buy some...I have never seen a gecko refuse them. Some people worry that their geckos get "addicted" to these, I would be more worried about an animal that hasn't fed in weeks and may be starving to death, you can "worry" about weaning him off of these later. Most healthy geckos will eat almost anything you throw at them that they can overpower & stick in their mouth anyway. Make sure he has a shallow water dish that is filled at ALL times. Also have a calcium dish if you don't have one already. Try mot to bother him/her too much (that is the hard part). And lastly, you may want to try to get an appointment with the vet asap...it could be parasites or an infection or ??? Good luck!