make a note of the colour bands so you know the value before it burns out!
You could try resoldering it to the board, but if it got hot and melted the solder then it'll do it again. Of course, it could be getting hot because it's loose and resoldering might clear the problem.
You could end up with a meter checking around the board, have you any experience on that sort of thing? If so, and you can't read the bands then you might measure the value of the resitor.
A photo would help and you'll get assistance and advice from here.
As always you /must/ check that you've turned the welder off and removed the mains plug from the socket before poking around inside. Also be aware that anything that looks cylindrical with two contacts may be a capacitor and may still hold a charge.