What Causes Stomach Ache,headache,fever And Sweating?

Hello Doctor,My 4 year old boy fell on his face while someone was pulling off his boots at daycare. This was two days ago and had some bruising and swelling on his nose and under his eyes. The swelling and bruising have gone down significantly within one day. But this morning he woke up with a tummy ache and a headache , fever and sweating after his nam this morning... is this related...should I take him to the doctor s?Thanks