I've noticed, since last week, some strange dots or even damage from one side through the other on some leaves of the celery I'm growing for the first time. Some leaves also became slightly wrinkled.

At first I even thought those dots were yellow... maybe caused by the high temperatures we're having where I live - or a magnifying glass effect, caused by drops of water, when my kid went and started spraying and watering the plants I have inside the house, during the day and causing some burns; but looking at the pictures it does indeed seem to be some kind of disease. A fungi, maybe.

Any ideas, about what it may be or how to take care of it? Thanks in advance.