I'm also a huge fan of UVA/UVB for ill reptiles. I wouldn't say you need to go out and buy an expensive light setup but instead take the little one outside and place it under direct sunlight for 10-15 minutes a day. I did this with a very skinny/beaten up crested gecko and within a couple days it was eating like I've never seen a crestie eat before.

Using tongs or a cheap pair of tweezers to hold the prey and get it wiggling around may entice a feeding response. Mealworms aren't the most active prey item and crickets are amazing at hiding.

Good luck and keep us updated!