Hay fever suffers, advice please

[TomRipley]

Last summer my little boy (just 5 at the time) developed hay fever symptoms for the first time.
Bad symptoms, completely swollen shut eyes etc, really suffered and came on quickly. Over the counter products for his age did nothing. He was prescribed a nasal spray, antihistamine liquid and eye drops to have every day which worked fantastically.

My question is, now spring is here, when should he start taking his medication again? He's showing no symptoms at the moment but should I start now to build it up?
Complete novice with hay fever so any other tips/advice, apps that help keep track of pollen count would be appreciated too!
TIA

Considering that your boy sufferes so badly take everything all through hay fever season, not just when suffering.

I would definitely start the nasal spray now, that is what I have done with my DD who suffers from really bad hayfever. They can take a while to take effect. My understanding is that the oral antihistamines act more quickly, so maybe use those when he starts to have symptoms

Tree pollen is out now, has been for a month or so, so good to know he's not sensitive to that! Def start it now.

I take it you know all the other things like washing face when coming in from playing outside, damp flannel wiped on hair, change pillowcase frequently, hoover more, maybe bedspread (or sheet) on bed in day that gets removed at night?

He might not want to, but sunglasses worn outside help - the bigger the better. Also vaseline smeared just inside nostrils on really bad days helps catch some of the pollen - but looks odd unfortunately.

Thanks all!
I didn't know any of those things @TheSpottedZebra so thank you. I do have hay fever wipes and a balm I bought before getting the prescription meds I can use.

Tree pollen? I'm such a novice, is it worth trying to find out which pollen affects him so badly? I think it was around mid June last year that it came on if that's significant at all, his birthday is May and I know he was ok then.

I will start the nasal spray, he hated it all so much last year especially the eye drops so didn't want to give it unnecessarily.