An inward burn is characterized by the filler burning inward as you draw on the cigar, while the wrapper and binder fail to remain lit.   

CAUSE

Inward burn can be caused by poor rolling, uneven lighting, and/or bad fermentation.  In addition, inward burn is frequently caused by  an over saturated wrapper or uneven humidity within the cigar: meaning the inside/filler is drier than the outside/wrapper-binder.

REMEDY

“Fixing” an inward burn can be easy, frustrating, or down right impossible.  Results will vary based on the severity of the problem.  If the problem is severe, it may be best to cut the cigar just behind the burnt area and start again.  Otherwise, you can attempt to relight the wrapper and filler at the foot of the cigar while puffing to draw the flame into the tobacco.  In the case of an inward burn, it may be necessary to char the wrapper and filler tobacco to help the burn rate catch up.  Also, keep the flame away from the center of the cigar to not exacerbate the situation.