Graston is awesome, it CAN be too much in the hands of someone less experience! My chiro uses that on me from time to time. All Active Release techniques (tool or hands) can be excruciating but usually only during the application, as you found out. Sounds like you've a good one! There are still a few out there that think it must leave bruising and residual pain/soreness to be effective but that's just not true.

Sounds like the voodoo magic was the perfect followup - hope you continue to feel better!