very good responses, the molar thing I second, check that. Try motrin instead of Tylenol, as it will help decrease the actualy swealing and tylerol wont, plus it last longer and is less harsh on the liver if you have to give regularly for a while.
Plus, don't over stimulate. At night keep is simple. No lights, no talking, maybe play a very soft CD of classical music or something in the backgroud. It's really hard to give advise on this becuase I don't know what "soothes" your child. One of mine, like being touched and rubs and the otehr just hates it.
If you can rule out any medical issue and you belive it to be behavorial then, I'm sorry but the crying thing might be your only option. Believe me, I know I hate it too and I tried everything, read everything and used it as a last resort, but after 3 - 4 days of really crapy sleep, hours of crying it did work on both my kids, and we sometimes have to revisit that technique (but only for one or two nights on a re-program) to establish a good sleep behavor.
I assume you are doing all the recomended pre-sleep routines, and going to bed at the same time, regular stuff. Otherwise - make sure to do that. Especially with it staying light longer the schedule is what kids grow to depend on to cue their body to go to sleep and stay asleep instead of assuming it's another nap. (which your child might be thinking it's nap time) I don't know just thougths.
Good luck, take naps if you can. And take care of yourself. Becuase a exhausted mom is hard to be as well. TAke care