I think starting over might be a better option. Just my opinion. Did you have a humidity dome over the flat to help germinate the seeds? Once they break ground is when they go under the lights only an inch or two above the plants and they no longer need the heat mat. What is the electrical cord for in the cell on the right? Also, is there a significance to the carpenters square laying on the flat? Keep us posted on what you decide to do.

You can salvage them by transplanting them DEEPLY into new containers if you wish. You bury all that exposed stem right up to just below the leaves. New roots will develop.

Then set them under the light and lower it so that it is just a 1/2" above the top of the tallest plant.

Otherwise, start over.

Dave