It's a charging effect. Deep crack on the left side of your image did not get coated with conductive material good enough. In addition small place in left upper corner is too bright, its also is a charge effect. Small piece of your specimen was chipped out after coating or was not coated good enough.

Increase time of coating, decrease accelerating voltage when taking pictures.

This sample is improperly coated. Thus charging occurred which caused this distorted image.