My Son (4 Years Old) Had A Fever Yesterday (102.8F)

My son (4 years old) had a fever yesterday (102.8F) , he was acting sluggish, complaining of headaches and he had no appetite. We did give him childrens Advil at bedtime to help him get comfortable. This morning, he woke up and played normally all morning had breakfast and are a normal lunch. He hasn't had any Advil since last night 8pm. I just checked his temperature now, and he's running a fever (101.7) but has complained about anything and everything else is normal. Is it just his body getting rid of the virus? Or should I be more concerned?