iPhone 6s with 9.3.5 update -- keeps crashing

My phone crashed yesterday and I thought nothing of it, just did the home button + side button restart and went on my way. But it's crashed three times today. I updated the software overnight on Wednesday, I think, and I was just wondering if anyone else was having a similar issue?

Full disclosure: my phone DID take a swim in June, but after spending a few days in rice it was working and seemed to have made a full recovery. I'm not sure damage would have taken this long to set in, but it's a possibility, unfortunately.

Thanks!