I unfortunately had a similar experience with my tonsillectomy. I didn't do the self pleasuring you did, all I did was accidentally snore while sleeping and it opened a flood of blood on day 2. Ice water slowed the bleeding, the office used nitrate (I think) so cauterize where they thought it was from. Later that night it randomly opened again but this time I couldn't get it to stop. I was basically coughing on my own blood, and nearly fainted while I was wheeled into surgery. They pumped my stomach because I swallowed so much blood. Luckily the second surgery went well and while I did have minor bleed days later, nothing to that extent.

I'm glad I did it, but almost dying really makes you think having strep 5 times a winter might be a little better lol

P.s., I'm also an adult. Had this done at 26. It was a horrible, traumatic experience.