So I've found that I can play one short piece, a quiet one, on my acoustic piano, with no adverse effects. I use earplugs and earmuffs though, so it only gives me limited enjoyment, but my wife enjoys hearing me play her favourite pieces. Last night though I played the same piece a second time, and this morning the crickets and cicadas are back in my head again. Not any louder than before, but they'd been getting quieter over the past week or so but they are back up to the level they were at a week ago. I guess I mustn't rush my recovery then. I'll take a break for two weeks then go back to just one quiet song at a time.