Good day. I discovered an asymmetrical fold on the child's leg on one …

Good day. I discovered an asymmetrical fold on the child's leg on one of the legs on the weekend. The fold is present on one leg and not on the other. On Monday, the fold appeared on the third leg, and I did not contact the pediatrician. Yesterday, I found that it had disappeared again and remained on one leg. To the pediatrician on Friday. In the first month, we were at the surgeon, pediatrician, and did ultrasound. No deviations were detected. How critical is the appearance and disappearance of folds? What could this be related to? Does it wait until Friday or does it need to be urgently rushed to the surgeon?