Aww, it does look very much like yellow fungus ?, I hope I'm wrong, but yes, try the
bath and see if it scrubs off (gently), but please do get him to a certified Herp (reptile) vet that absolutely has a lot of Bearded Dragon experience. Don't take him to a general vet because that's typically a waste of money, and if you can help it avoid "exotics" vets that say they have reptile experience, as they are not reptile specialists either, and most of the time people end up spending money and accomplish nothing, then end up spending more money to take their beardie to a certified Herp vet anyway. If you let us know where you live we can help you find the closest certified Herp vet to you. Yellow fungus is a tough infection to get rid of but not impossible, the most important thing is to catch it early and start treatment early so it doesn't spread. That's the key, keeping it from spreading. So washing the spot in the diluted Betadine or Hibiclens, patting it dry, and applying an antifungal medication that contains either Miconazole or Clotrimazole as it's active ingredient (female yeast infection treatment creams, use a 3 day treatment, not a 7 day treatment, as my Herp vet told me the 7 day dosage is too weak), and doing this 2-3 times a day starting immediately will help tremendously with stopping it from spreading. Also, no more
bathing until you see the Herp vet and it's diagnosed and you speak to them about it, as dampness allows fungal infections to thrive. So keep him clean and dry, and keep his enclosure clean and dry. I don't know what you use in his enclosure as a substrate, but please get rid of any loose substrate like sand and just use paper towels for now, that way you can change them often and it will be much easier to keep his enclosure clean and dry. Chances are that if it is Yellow Fungus it is in his enclosure and on everything inside/on top of his enclosure. I'd take everything out of his enclosure and disinfect it in hot water and bleach, and do the same thing with the inside/outside of the enclosure itself. Make sure you rinse everything thoroughly until all signs of bleach are gone, smell it to double check, but just keep rinsing it, then dry it thoroughly before you put him back in it. And then after you
bath him and dry him you can put him back in on the paper towels, and be sure to keep his enclosure clean and dry from this point on. If it is yellow fungus he'll need a prescription oral antifungal, antifungal injections, or both from the Herp vet to successfully treat it.
How long have you had your beardie? I know you said that you're a new beardie owner, and he is obviously an adult, so yes please contact the breeder as he most likely had this fungal infection before you brought him home, and it's highly contagious so chances are that other reptiles at the breeder's are also infected. How old is your beardie? Did he have that spot when you brought him home, or did it show up since then?
I hope he's doing okay and it's something completely harmless!
