One project, I let my rotary blade get dull and had material fuzz in my beautiful mat. I remembered that duct tape will fix almost anything.
I slightly bent the mat as I used strips of duct tape to lift out the fuzz, by pressing with my finger right along the 'cut marks' from the top the tape. I peeled the tape off (like removing lint off clothing) and after about 20 minutes of work, it looked almost brand new all over. It can't heal itself if there is something stuck in the blade marks. Packing tape works well too. Hope this helps.