Thank you for your query,
The red dot like pimple is looking like a bacterial skin infection
like an evolving pustule.
You can apply an antibacterial ointment like mupirocin
thrice daily for 5 to 7 days.
If the lesion is not decreasing or it is increasing consult your Pediatrician
for examination and treatment.
There is nothing to worry about birthmark
unless it is spreading, having color changes are associated with any discomfort.
Hope I have answered your query.