It looks ok man,poss mag def,but your prob more than half way thru your flowering and you`d be harvesting before you could correct it in soil IMO,nitroegen def is totally natural late in flower and you really want to be seeing it,as mentioned above you dont want your buds full of N when you harvest,dont forget to flush for about 10 days with straight ph`d water prior to harvest,good luck, RM.Peace