The plants will never heal you just cut the top off. The plants are going to be in shock for 3-5 days. If u want bushy plants you should supercrop them the whole time they are in veg. 3-5 days before you decide to flip them to 12/12 also lollypop them next time. For now just grow them untill they are 25-50% of the hight you want them to finnish at then flip them.