First time surfing (in Lima)

I just went surfing for the first time during my trip to Peru, in Lima (Miraflores) specifically. I'm not really a strong swimmer (don't practice/swim much), and haven't really swam in non-still water before, so I wore a life vest the whole time. Idk how well I'd do without one, but probably don't want to take any chances out here.

I'm taking private lessons from a certified guide, but there are some language barrier issues, and I couldn't get some of my questions answered (properly) after the lesson.

The place we were surfing had a rocky/pebble shore, and when we were getting back to the shore, the waves pushed me against the shore a couple times, and it hurt. Not too bad, and I could imagine it going a lot worse if my head made impact with the rockets. What is the safest way to get on the shore in these situations? I was just following the guide, who didn't really instruct me what to do.

Right after I got on shore, I had a very bad headache and was a bit dizzy when standing. The pain mostly went away if I crouched or kept my head down. I was fine after 10-15min, but I'm wondering what is this pain from? Impact against the shore due to the waves? Swallowing saltwater?

I got 4 more private lessons, and want to avoid some of these issues going forward.