Thanks for coming to healthcaremagic for your query.
I am hoping he is taking orally well (feeds/fluids/milk etc), passing good amount of urine and not vomiting
From the symptoms described, it appears he has got respiratory tract
infection, commonly due to viruses in this season.
It takes couple of days for infection and fever
1. Fever doesn't subside
2. He is very lethargic and not interested in anything
3. Vomiting a lot
4. Not passing urine for 6-8 hours
5. Breathing very fast
In this situation, you will have to get her checked over by Pediatrician
If runny nose is leading to blocked nose at night and difficulty in sleeping, Saline Nasal drops may be helpful to clear the nose
Wishin him a speedy recovery
Dr Tejas Shah