She could grab a towel from the poolside

Now that more people had entered the changing room, it was going to be difficult to go to the lockers without being seen, let alone all the way to the reception area. She could hear the group of girls enter their own stalls now and knew it might be her last chance to rush through the corridor unseen. Then, she realized there had not been that many people at the pool in the first place. By now, with these girls here, the pool was likely mostly empty. She could probably rush there and snatch an unattended towel before anyone would seen her.

She had to be quick though, which she found to be surprisingly difficult. She could not run all that fast on the wet floor, and she was too afraid of running into someone. Nevertheless, she made it to the pool showers quick enough to avoid being spotted. Adrenaline pumping, she hid behind the wall there and starting looking for something to cover herself up with.

There was a bulky foam mat nearby that she could use as portable cover. There was a towel draped over a white plastic lounge chair on the far end of the main pool as well. She could try to swim there, but there were some people in the water already. With the mat as a shield she could maybe walk along the pool without anyone realizing she was naked.