Did I just eat undercooked chicken?

My roommate made chicken 2 nights ago, and they were thick chicken breasts. She said she checked with a meat thermometer multiple times to make sure it was 165 degrees. When I ate some, I noticed the inside was slightly pink, shiny and a bit chewy. It didn't exactly look raw, but it was really slimy and chewy. It tasted fine and the crust & outside was fine. I only had like 2-3 bites of the chewy part. Please help.