Candle sweating is common and not unusual. It occurs during temperature changes from cold to a warm room, or while sitting too long in a hot environment. Sweating is the fragrance oil coming to the surface of the candle in sweat beads. It does not affect the way the candle burns or how many hours it can burn for.

Your wick may be too short; you can fix this by blowing out your candle and using a paper towel to wick up some of the melted wax. Relight, and your flame should be brighter and bigger. Your candle may have burned too long and may have a carbon build up at the top of the wick. This is a common problem and is normal for candles. Trim just the tip of the wick off, this should fix your problem. Your candle may simply need a rest. Relight after you've let it cool for a couple hours.

Your room may be too drafty, light in a draft free environment. Your wax pool has a memory-- if you don't achieve a proper melt pool on your first, and subsequent lights, tunneling may occur. You can scrape off the wax around the edges and relight your candle. Never burn your candle for longer than 4 hours each time.