Drain site infection? What’s the white tissue? What’s the yellow discharge that stains the gauze? (Photos)

I got a tummy tuck 32 days ago the drain was removed on day 13th. The scabbed closed but then a stich was coming out the doctor removed the scab. He called it detriment and then told me I didn’t have an infection and that I could shower and just cover it with gauze and clean only with water and mild soap. It’s been 3 days since he removed scab and did debriment... I’m so scared how is this looking? Only stains a tiny bit.