If it wasn't a full break it should be fine as they usually scar over and keep on going without any intervention. Full breaks are a lost cause. It may wilt a bit but once it shows signs of perking back up remove the tape so air can get to the area.

Dave

I accidentally completely broke a stem of my KBX this weekend. I re-cut the end of it and put it in a mason jar of water. If it roots (and I don't see why it shouldn't) I will replant it. Hopefully the little 'maters that are on it will still carry on. A stem on one of my other plants cracked a little bit a couple of weeks ago when we had a big wind gust and I just straightened it back up and supported it with a clip against the side of the cage, and now I can hardly see where the injury was. So you should be fine, as Dave said.
Edie

People thing a mend is successful if the tomatoes ripen but if you just pick those tomatoes they will likely turn red. I'd concentrate on the remainder of the plant by supporting and training a new lateral branch to keep the production flowing. A bend (Kink) in the branch is less of an issue and tape is less needed than string to keep it from bending down again.

Three days ago, main stem broke when I neglected to properly secure it my plant, it rained and weighed down everything causing this. Unfortunately the break is on a stem that has half of the flowers and was the most vigorous.

The break was about 2/3 clean snap and 1/3 connected remaining. I panicked and just made do with what was handy, mostly because I didn't want it exposed to the spores in the air and microbes that the rain carries in the wind from the leaves of the higher trees around. Maybe I just made it a breeding ground, but so far, choked or not, it appears mending. I think one more day with the cut tube and I'll undo the wires, hoping scar tissue has the wound protected and then I'll better support it and see.

Don't know if this will help or if it was a mistake, but take a look in case it gives you and (good) ideas if it happens again.