Unable to swipe down from red dot

Restart it by pressing both the Crown button and side button at the same time until the Apple Logo appears

Or if it’s not responding to touch at all, you might have water lock enabled: How to use Water Lock and eject water from your Apple Watch - Apple Support

nothing happens when I spin the side dial. The screen does not pull down from the red dot. If I touch the crown and the side button all I get is siri