I recommend returning to Treasure town, seeing as you have no items. I also recommend you get a bunch of Reviver seeds. Those come in real handy, as do Stun and Sleep seeds. If your Cyndaquil knows smokescreen, have it use that by turning off all its other moves, then turning its fire type moves. As for you, just use moves and the 2 seeds I mentioned to immobilize it if Smokescreen wears off. If you do that, you should win very easily.