What to do after I caught my swim coach checking me out?

So I’ve been taking beginner swimming lessons at the pool and this week it was finally warm enough to swim in the ocean. So our classes were moved there, but there are no locker rooms, so people just change out in the open but usually under a towel or in the shade or something.

When I arrived for my lesson, there was almost no one on the beach and I found my coach waiting for me. I needed to change so I expected my coach to turn away or at least respectfully avert his eyes. But he just kept standing there and said “ok I’ll just wait for you to take your clothes off.” So I stood there waiting for him to turn away but he didn’t, and finally he said “so are you going to swim in that?” (gesturing to my baggy shirt and cargo pants)

I said “uh no” and he said “ok, so you brought your swimsuit with you?” And I said yes but he just said ok and didn’t make any move to turn around or give me privacy. I was already wearing it under my clothes and all I had to do was take them off. but I hesitated because if it was in my bag or something, I was like was he going to stand there while I got naked and put it on? So i just did nothing.

I waited a few minutes, pretending to act busy and apply sunscreen, but still he hadn’t budged, just fussing with his things and checking his bags and stuff, so when he seemed distracted I turned slightly and quickly yanked off my t shirt, as my one-piece was under it. But when I bent down to take off my pants, I looked up and saw he was intently gazing at me, it seemed like he was checking me out because he was staring through the corner of his eye.

I was purposefully wearing a full coverage swimsuit, it was just a shapeless black rectangle. But when I bent down to get my trousers off, I could feel my cleavage spilling out a bit over the top and the sides and I got nervous. Idk why but for some reason at that moment I glanced up and his eyes were latched onto my chest. When he saw I saw he was looking there, his eyes quickly darted up to make eye contact, and he blurted like “yeah it’s ok! don’t worry! you can definitely leave your bags and stuff on the beach!” even though I hadn’t asked and I wasn’t worried at all lol.

I mean, he can already see me in my swimsuit during the lesson, so it’s not that, but it was weird how he gleefully watched while I got into awkward and vulnerable positions to remove my outside clothes, and went out of his way to stare. And I might have been imagining it, but during the lesson, he kept trying to find ways to touch my body a bit more than necessary during the lesson, especially my thighs and the side of my body next to where my boob is, and each time his hand lingered just a bit too long… I thought I was being paranoid but I feel more and more uncomfortable the more I think about it. Should I do anything about this?