Thank you for your query.
You did the right thing by rinsing the mouth. The eyes are red because the spirit in the colonge is irriating your son's eyes. Do wash them with water frequently and the redness
shall subside over the next 2-3 days.
You need not worry about the cologne that your son has swallowed, if any. Being aromatic spirits they get evaporated fast.
I hope I have answered your query to your satisfaction.
Wishing your son all the best.