they do look under waterd mate, i no its hard to get it right, but you need to water them enough each time so you can see water running out the bottom of the pots, you should be able to turn the plants around, at that stage you should be giving them a water every 2 or 3 days and using nutes every other water as well, or even 2 feeds to 1 just water, i would start watering every 2 days or 3 mate, try and fill the post up each time so you have got run off coming out the bottom, then let the plants sit to suck the water back up then allow it to drain away, check humidity as well, and temp, you dont want the temp to high, in a small space like that the temp will soon rise and humidity will fall and dry the plants like that, also if you have got a fan blowing directly on the plants then this causes the leaves to dry out, you need the fan blowing above the plants, or just have a fan in the top of the grow blowing air out the cupboard and allowing it to suck air in at the bottom on its own, this will increase humidity and should help the plants,
so id give them a good water with some nutes in, not a strong mix as you have damaged leaves so start at half strength and keep watering till the water is running out the pot, i have my plants in 3gallon pots and i water each plant about a pint and a half, or 750ml of water, and keep checking till its running out the bottom, not gushing out but just trickling out the bottom of the pot, make sure the drain holes are not blocked as this causes root rot, so give them a water and keep checking for run off, they will need watering every 2 or 3 days depending on temp, you should be able to turn the plants around,