Tomato stem bent, will it heal?
From experience I can assure you that it will thrive and possibly do better than the other vines of the plant. The important thing here is to NOT change the current angle by attempting to straighten the plant. You can tie it up to a secure stake to prevent further damage, but do not straighten it out. That will most likely cause it to lose the "flow" of nutrients that has re-established itself in order to survive. Remember - all plants are basically weeds and will survive despite our loving care - usually.
If it does become limp, simply cut it off and set it in wet potting soil. Keep it in a shady area (I use my carport) and out of the wind also. I use Jungle Growth potting soil and have successfully saved identical vines and as well am now using this procedure to start my second crop tomatoes. Good luck and feel free to ask, I may be a mere mortal, but I do have luck with tomatoes.
If you don't have time to do it right, when will you ever have time to do it over?