Tom and Tea. I've only just picked up on this because so much of this thread these days is asking about regulations.
I trust Tom, that you'll follow Tea with a full checkup - SASPO. If your doctor doesn't want to bother referring you, insist.
It's true it might be little to worry about, but you must find out why it has changed.
The altimeter needle thing. That's an odd one, but not for the reasons you may think. Some people see a regular flow of the needle, say when climbing, and this is constant. When others look away, and then back to the needle, it seems to have stuck while you're not looking, but then resumes normally with its rotation. This is normal, and has to do with the brain buffering information - and handing you what some sub-processing thinks you should be expecting.