Whats this spot on leaf?

Today I transplanted my plant. Different soil, starting soil mix with root growth nutrients mixed with pear lite. I accidentally tore a few roots but nothing major. 8 hour later i see this spot. rest of leaf is fine and rest of leaves are fine (except the bottom leaves that are yellow and curled at tips). The soil ph is 6 at the bottom and 7 at the top. It cant be nutrient burn cuz it doesnt have any hardly in it, and its no where else on the plant.

Can anyone tell me what this spot is from and what should i do to fix it?

BLACK DOTS ARE DIRT FROM TRANSPLANT NOT BUGS!

It looks to be a burn of some type, maybe from a droplet of water?
If its just on that leaf just yank that leaf.
and if it's some sort of disease that started on that leaf youll isolate the problem.
But id watch that plant closely, If you have more plants id isolate that plant, and see what happens. If nothing else happens in a week or two id think that your safe.
But it looks to me like when you splash nutes on the leaf's, but id play it safe.
peace

ya it could be from a drop of water or something... i dont remember it being there though cuz i was touching the leaves a lot

I know this happend on my first grow and i freaked out and had to figure it out myself i didnt have the net at that time.