6/4/26 Today I had singing class as usual. But this time instead of going directly to college by car, I walked there with my RevivThree on. Once I got on my t-shirt, I noticed the stretch marks on my forearms. As usual, it was particularly present in my left arm. But there was a bit on my right arm too. This is the first time this happens to me after singing class. And even in general I haven't experienced the marks for a while, although I haven't massaged directly on my arms or payed that much attention to them recently. My hypothesis is that the mouthguard (and walking to an extent) allowed the body to absorb the effect from the practice much faster, or "in one go", as opposed to maybe getting added more slowly to the system. This confirms my suspicion that singing is another accelerator, since it works biomechanics through sound, breath and more. As an extra, I've been improving each class for a while now. Even though I basically don't practice (only other songs while doing other stuff) and even listen to the songs we do very little (don't tell my teacher this). Edit: added a pic of the right arm.