Turns out that the plasterboard cutter I bought is also highly effective on thumbs.
Thankfully I can type pretty easily on my laptop but using a phone or writing is now rather a challenge.
(Agent Pr1ck llǝɯs ǝɥʇ sʇI ˙ǝɔɐld sᴉɥʇ ǝʇɐɥ l, Tue 10 Aug 2021, 22:10, archived)