Children are prone to viral rhinitis and may get it as much as 6-8 times a year.
The disease is harmless and resolves by itself, and is spread by droplets(air, touching objects)
It could also be allergic Rhinitis. Do you have a history of allergy in the family? Does anyone have asthma?
A
Complete Blood Count would help.
If no issues on that, you can have your mind at rest and continue with symptomatic treatment.