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
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!!!!