Are you thinking about:
- Training by yourself for a few weeks before joining your usual group?
- Or training with them, gunning it for 20 minutes until you're blown before jumping out saying you have got a work meeting to get to?
- Making all your sessions private on Strava 'cause you're going to be slow?
So: Suck it up. Park your ego at the door, walk in the pool building and just do the session as best you can (a slower pace) without any special compensations (e.g. a pull buoy).
And then post it unedited on Strava *without* a witty title like "too much xmas pudding".
Most people won't even notice you're slower than normal. And those who do will just shrug. You can tell them why if you want but it would be even more humble to just stay quiet and get on with it.
Do that and you will improve as quickly as possible, your friends will respect you more and your sense of self will be far less god like.
So go on, do the work and if you are good enough to beat everyone come the big race, you still will.