Good day my son has red dots on his face that turns into scabs and his nose also has a sore on the inside... what can cause this? he is 5 years old

Rash: It would have been helpful to see it. Depending on when it appeared it could be impetigo, herpes, measles to mention few possibilities. Consult a physician if the rash is still present.

Doctor can examine: Rashes are hard to describe or visualize in words. His pediatrician can take a look in-person, or sometimes a video consultation is adequate. If a child has a single outbreak of little dots that scab and heal, over a course of 1-2 weeks, chicken pox is a likely cause... but kids get vaccinated so most have some protection. Impetigo bacterial infections, etc..., can also cause scabbed dots.