Did you dry burn the cotton by accident? Cotton can only be fired when wet.
If that's not the case, you could have adjusted the coil by accident when you cleaned and re-wicked it. Thereby, creating a short or hotspot on the coil.
Take the wick out, if the coil was adjusted, you can try to pinch the coil back together with tweezers and fire very short bursts to heat it up and work out the short. Then re-wick. If the coil was not the problem, just put a new wick and drop some
juice on the cotton to prime it before putting it back on the atty.