how bad is it? set the chain to be taut at the tight point (so there's like an inch of play or so in the chain). if the chain is loose enough at the loose point that you can take the chain off the cog or chainring, buy a new chainring. If it doesn't fall off, then i don't think it's a safety issue. You'll need to replace it with a more expensive one regardless if you want to get rid of the variance in slack