Need advise ASAP - Crispy discolored leaves.

Well she's like..... 5 days into flowering, noticed these crispy wierd lookin leaves, what's causing it? Terrible pictures, was in a rush.
Reason i need advise asap is because i'm going to the store as soon as i get a good answer, it's about to close.
Also, what would i buy to fix it? Kinda seems like a deficiency to me.

Really need an answer asap

http://www.marijuana-seeds.net/Thanks-ThankYou.htm

https://www.rollitup.org/marijuana-plant-problems/216537-self-diagnose-your-plants.html

hope this helps

Bumppppppppppppp

Back from the store..... I figured magnesium deficiency so i picked up some epsom salt.

Edit: I'm not feading her anything i buy till someone confirms it's what i think it is .

Anyone????????

No one ????????