First, assist-feeding should not be done at all in my opinion. Unless it is emergency. Plus, no offense but you do not have experience to do so. These things can potentially hurt them.

Second, what is your temperature and humidity level? And what is temperature on the basking spot?

Third, why are you using two heat source? What temperature are you trying to reach?

Fourth, DO NOT use UTH without a thermostat! That will definately burn and be lethal to bp. Get a Hydrofarm thermostat. It is less expensive and very good.

Finally, let him/her get settled. Let it be for awhile until you feed him. Also if you can, please ask the feeding schedule and feed to the place where you bought from.

"Snakes don't bite. Just humans."