While Chinese publications are often more generous to TCM treatments, they still conclude scraping/Guasha is likely worthless: https://www.ncbi.nlm.nih.gov/...articles/PMC2827462/

I've had the Graston technique done on me for calf/Achilles issues. It worked great. One year or so out and I haven't had any more issues.

n=1, so take it for what it's worth: Guasha has worked very well for me. However, that's for an easily accessible shoulder muscle, and I scrape quickly for several minutes until the area is red. The following day it looks bruised. I spend a bit of time poking the area with my thumb before scraping to make sure I've found the most painful spot, which isn't always the same area that is in pain when I'm actually using that muscle. Relief is usually immediate. I can return to my normal workout the following day.

When I ruptured the plantar fascia in my left foot, part of the rehab was Graston scraping to ensure that the scar tissue healed in line with the fascia instead of as a general blob. I had a complete recovery in two months.

However, I don't see the benefit in your case because the injury is already months old and it's not clear to me what the injury is other than deep. E.g., was there a muscle tear? Exactly what is the injury now, what are the symptoms, and what is scraping of that muscle supposed to do at this point?