Warning tmi! Babys poop photo- worried mama

Hi guys'

Again warning! I'm just looking for some advice.

My 6.5 month old pooped earlier today and it was fine no issues. I just changed her bum again, and found this.

She hasn't had solids in a few days. She had a diaper rash and the dr said to avoid solids to see if thatd help clear it. Diaper rash is gone now. But now I'm concerned about her dark, mucus poop.

Any advice? I'm planning to monitor it and speak with a doctor tomorrow.

To add- she is strictly formula fed