Hi and welcome!
What type of torch are you using? And how long have you been working hot glass?
If you are working on a Hot Head, you may be bringing your glass too close to the flame near the face of the torch, causing the glass to burn. Try and keep it out a little further from the torch face...like these pictures show:
This is my Hot Head torch's "sweet spot" where the flame melts the glass perfectly without burning it. Notice the distance from the face of the torch, and how I don't have the glass actually in the strongest portion of the blue flame "cone", but instead just at the tip of the flame...
Hope this helps!
