Control center does not appear on Apple Watch

Well, the solution is quite simple. Most of the time, a normal restart of the Apple Watch will fix this issue. To restart your Apple Watch follow the following steps:

1. Press and hold the side button until you see the Power Off slider.
2. Drag the Power Off slider.
3. After your watch turns off, press and hold the side button again until you see the Apple logo.

If your Apple Watch is charging, take it off the charger first. When your watch is charging, you can't restart it. 

But what if you've restart your watch and the problem is persisting? Well, then the time has come to do a force restart. Force restarting your Apple Watch is a last resort, only to do when your watch is totally unresponsive. Don't ever try to force restart your watch when installing an update of watchOS, this can seriously compromise your watch.

To force restart your watch follow the following steps

To force restart your Apple Watch, press and hold both the side button and Digital Crown for at least 10 seconds, then release both buttons when you see the Apple logo.

Apple Watch doesn't scroll on screen - Apple Community

try just swiping up from the bottom

touching and holding doesn't work all that well on my watch, but I suspect it's because I have a case.. which likely impedes me from touching as low as I otherwise could. swiping up works every time though