Exactly. The isolation of the burnt leaves is a dead give away of a heat source. If this was a deficiency of some sort, it would most likely be visible elsewhere on the plant but, from what I can see, the rest of the plant seems to be OK. If it were nute burn, you'd see many of the leaves respond the same way.That side of the plant has been placed to close to cfl and now they are bleached/burnt, expect this to reduce yield as the damage and stress to the plant is not localized. Raise the light and be more carefull in future.
No way is your plant had it . Defoliate, Am not mega experienced but people will have varying views about the state of your leaves because it could be so many things. I would add 1 tablespoon of epsom salts to 5 litre of water and and give it a good water , take off all the badly damaged leaves and continue as normal. Might want to give it a bit cal/mag as well and a couple of feeds of grow nutes. People will probably slate this advice but have had a similar problem and thats what i done and it worked. Make sure that the dark period is 100% dark as well. Good luck !