I let my friend borrow my bike today so he could get a feel for disc brakes. when he gets back to my place he said i bashed the back tire going over a curb. i check it out and sure enough thers a flat spot on the rim. the spokes all aroudn it are super loose. how bad of a flat spot can you get away with before needing a new wheel altogether? if i retighten the spokes will i be fine or is it dangerous to be riding on? there are no cracks in the rim.
thanks for you help.

JJ