Weird pimples on my cannabis leaves

Hello, I'm growing for the first time and I have 2 auto plants (Ak 47 x Jack). Recently, I found weird spots in the leaves on one of them, they seem like pimples and when I see with a magnifying glass I can see a little bump and a llittle white hair comming out of it, and if you see it with backlight the bump looks transparent. However, I didn't see any bug under the leaves or anywhere else on the plant, but this seems to start at the bottom (as you can see, the leaves are also turning yellow), but it hasn't gone higher yet. They where stressed in the past because low temperatures and PH problems, I tried to solve them and the plant got better but now I found this and I'm worried. Sorry for my english but I'm desperate for answers, I don't know what to do and the plants are almost in its end so I want to be sure everything is alright.
Here you have some photos of them:

I’m not seeing anything but a nice looking plant.
You got this, no problem.

Minor virus?

A little penicillin should clear that up in a jiffy. lol j/k Looks very common. No issues unless it spreads, them we might need a topical ointment.

Looks like trichomes or 'trich' bumps on the leaves. Grab a loup and take a closer look.