You can try a glass blower. If you don’t have one in the community, try a science department at a University. Most scientific laboratories and University Science Departments have them on staff. They can heat the chip to the point of softening of the glass resulting in a smoothing of the chip. The danger is in the cooling, as the glass can cool unevenly and create stress in the glass that can cause it to crack or shatter in the cooling process. They would probably have to cool it slowly by annealing the glass. A good glass blower should be able to do it right.
Harry Long, MD