I've been asking that question for days, haven't gotten a good answer. It's one of those rumors that popped up in the days after the bombing (when there were all sorts of rumors flying around), and people seem to have latched on to it, despite a lack of evidence. It just doesnt make sense:
1) The pictures show no burns on his hands. Burns, particularly severe burns, don't heal that quickly;
2) In the pictures, he had an IV in his hand. If his hands were, in fact, burned, the medical staff would have inserted the IV elsewhere; and
3) What would "burned hands" even prove? That he was so close to the bomb--holding it, perhaps--that his hands were burned? Because, if he was close enough to the bomb that his hands were burned from the blast, he likely wouldn't have survived the blast, and even if he did, there would have been a whole lot of other damage in the pictures (shrapnel, etc.).
In one picture, he has his fingers linked. He’d never do that if they were burned. Nope, that dog don’t hunt.
I just read an older thread linked here. It’s the one that had the first pictures of the stuff being removed from this Saudi terrorist’s apartment. That article said he was taken to the hospital due to shrapnel wounds to his legs. It didn’t mention anything about burns on his hands, and I think that bit of info may not be true.