Also, I'd also post a photo of your beardie along with photos of his entire enclosure and lighting, as it's best to get his setup and lighting correct now, while it's early, before bad husbandry causes any health issues. Most pet shops and even a lot of breeders give horrible advice about what lights to use for bearded dragons, what the temperature gradient inside their enclosure should be, what diet to feed them, what substrate to use, etc. The absolute most important item you will ever purchase for your beardie is his
UVB light, as they are desert reptiles and getting them both the adequate strength and proper wavelength of
UVB light for at least 14 hours every day, at an appropriate distance from the basking spot, unobstructed, along with appropriate Basking Spot, Hot Side, and Cool Side temperatures within the enclosure will be responsible for whether or not he digests any of his food, absorbs and processes his nutrition, Calcium, and other nutrients and vitamins, and ultimately whether or not he grows correctly or develops any Calcium deficiencies like Metabolic Bone Disease (MBD), which is unfortunately very, very common in a lot of pet beardies because of horrible advice from the pet store employees and breeders.
So listing his age, size in length from snout to tip of tail, size of his enclosure, brand, model, type (tube, compact, or coil), color, and wattage of both your
UVB light and your basking light, listing the temperature of his Cool Side, Hot Side, and Basking Spot, the type of thermometer you're using to measure the temperatures, what substrate you have in the bottom of his enclosure, and what his daily diet is (what is his live staple feeder and how many feeding sessions per day do you give him, as well as how many live insects per session does he get, as well as what his daily fresh greens and veggies are, and any commercial foods), and what Calcium and multivitamin supplements you are dusting his live feeders in and how often is a good idea so that we can help you get him setup to grow properly and stay healthy. Typically a lack of appetite in a new beardie has to do with relocation stress, but after the first week or two then it can be do to inadequate lighting, temperatures, etc.