Girls, shit! Changed diaper, and there's mucus, no poop, just like sno…

Girls, shit! Changed diaper, and there's mucus, no poop, just like snot ? I attached a photo below, don't look at it if you find it disgusting!!!! I remember something was happening with the older one, but we seemed to do nothing then. The baby eats well, weight is gaining, went to the toilet in the morning as usual, everything is normal, we're exclusively breastfeeding now, even don't drink water. Yesterday when he bathed, he drank a little water, can't be because of this? I think I should call the pediatrician or observe further