[Steve Swift]

A few moments ago I accidentally activated the stopwatch feature on the chronograph watchface (the red seconds hand). I closed it.

Now, I cannot find how to get the stopwatch to start.

What's the gesture that makes the stopwatch appear? I keep going into Samsung PAY...

[pizza_pablo]

Are you talking about a shortcut, on the watchface that starts the stopwatch, as opposed to going into apps?
Which watchface are you using?
You can take a screenshot and post it, here.

[Steve Swift]

Yes, I was referring to the default watch face (chronograph).

I fiddled around a bit and discovered that I had to tap the very centre of the face (the boss).

I suspect that the area that launches the stopwatch has contracted to make way for Samsung Pay. And that is why I kept going into Samsung Pay.