It looks like it could be bug damage. I agree with the
neem oil comment and would mix any 100%
neem oil blend (amazon) or hydroponic stores Einstine oil is good too but probably more money then Amazons. Mix the
neem oil at 2 TBSP per liter and add 2 or 3 drops of sunlight dish soap (original lemon scent). The soap breaks up the oil and acts as a wetting agent, it also traps any bug eggs and additionally washes bugs down to the bottom of the plant. The
neem oil is toxic to bugs and coats the leaf in a nice shine that keeps bugs and molds away, great stuff. The
neem oil and soap should be sprayed a few times a week. I like to alternate with that and a
liquid karma spray (always with dish soap in spray) and spray daily until week 2 of flower or when buds set in.