Go ahead and crop the main stem, in my current grow my Lemon Skunk stretched way up into the light during the first few weeks of flower and I supper cropped the main step and dropped it almost 1'.
Check my grow, its in the signature; I am now into about 35 days of flower and the main stem is doing a wicked left turn with buds doing another left turn to the light. Your plants will be fine, this is better than frying the hell out of the main cola. Surely this does stop growth until the plant heals up but that is what you are looking to do.
Grab the main stem and pinch and twist until the stem drops, then place where you wish. I like to tie up the branch/stem as it relieves some of the weight on the damaged area, the plant will heal and start to grow again in 5 -7 days.
regards,