If a candle shows bloom that's a good thing. Over time candles that are made of 100% beeswax, will develop a soft whitish film called "bloom" on their surface. It's an indication of the candle's purity and does not mean the candle has gone bad.
There's no need to wipe off the bloom but if you prefer it gone you can rub the candle with a soft cloth.
This is one of the first candles made by me a few years ago and is showing the whitish bloom.
Any candles that aren't made with 100% beeswax will not show bloom so in fact a pure candle should bloom if it has aged.