Wow, unlucky you.
I have experienced a very mild version of what you describe. If I have a really heavy day and get carried away the next few days can be a disaster. Sometimes it makes me feel like giving up

I think what you are describing is Embouchure Overuse Syndrome – search for “Embouchure Overuse Syndrome in Brass Players by Lucinda Lewis” – https://www.dansr.com/wick/resources/embouchure-overuse-syndrome-in-brass-players#:~:text=Embouchure%20overuse%20syndrome%20is%20the,injury%20suffered%20by%20brass%20players.&text=The%20reason%20is%20that%20the,the%20embouchure%20from%20working%20normally.

When it happens I try and overcome by really relaxing the lips using a didgeridoo. Sounds daft but I picked up the tip in some discussion group in ‘Trumpet Herald’. I started off with a length of 1.5 inch waste pipe and then found a reasonably priced didge on Amazon (if you are based in Australia I am sure it will not be too difficult to source one). I do long notes on the fundamental resonance – it also helps my breath control. I try and keep the note continuous for up to 30 seconds although I rarely get to 30 seconds! I then move on to buzzing pedal notes. I tend to find that if I cannot buzz pedal notes at the start of my warm-up then the rest of the session is not going to go well. I then give it a long break and typically the next session in the day is better. I know Greg is not a fan of the buzz but I am careful to use the aahooh setting and it works for me.

You mentioned that the trigger seemed to be the lip slurring – I have to be careful not to overdo them as I now recognise that they tire my lips more quickly than anything else. It is so easy to get carried away when you are competing with that retched metronome!!!!

Best of luck
Colin