Good day. A red small spot appeared in the baby at one month old, whic…

Good day. A red small spot appeared in the baby at one month old, which grew into a small ring of two rubles. We took him to a dermatologist, he sent us to another city for tests, we didn't take it there. According to him, it could be lichen or dermatitis. At first, they smeared acriderm, it seemed to disappear but then a ring in the form of pimples appeared, they started smearing sulfur ointment, the pimples went away, leaving a ring. 1 photo as it was 2 now Has anyone encountered this?