IT isn't unusual for dragons to lay on the bottom of the tank, especially if its too hot up on the basking area. We really do need more info about your setup and your dragon.
Other than laying on the floor of his cage..was he doing anything unusual?
You mentioned he fell when you picked him up. How high was he when he fell? A fall could cause all kinds of injures which could explain why he can't seem to right himself. I can't tell if the fall caused his later symptoms (ie head tilt or failure to right himself) without knowing more about how high he fell. Since my dragon will often tilt her head to one side when she looks up at me while I am holding her...what you describe about that aspect, before the fall, doesn't sound unusual.
Now if he was exhibiting head tilt, or looking straight up for no apparent reason, these can be signs of neurological issues or nutrition deficiencies.
Give us a full detail about your dragon since you purchased him. How long have you had him? What is your cage setup? How much, often and what do you feed daily? Do you have UVB light? What is your basking temp?, Ambient and surface temps? How about the cool side of the cage? What sort of substrate do you use? What is the weight and length of your dragon now?
The more information you can give us, the better it is for us to figure out what is wrong. However, if he did fall from a great height (more than a foot or two) and if he still can't right himself...or holds any limbs out at odd angles, a vet visit is a must. He could have broken bones in the fall, or have internal injures.
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PHLdyPayne
Forum Princess