Contact the GP, there are some great nasal sprays on prescription now (Dymista).
With hay fever medications, they need to be started at least 2-4 weeks BEFORE hay fever season starts. Because it's easier to stop the inflammation build up, because as once the inflammation starts then it's almost impossible to reverse it.
So meds needs to be started 2-4 weeks before hay fever usually in March and needs to be continued daily (whether there are symptoms are not) till the end of the hay fever season.
It's worthwhile checking pollen levels on days when you're going out. Sometimes that means not going out for me unfortunately.
Sunglasses can be protective and reduces the amounts of pollen entering through the eyes.
You also need to shower and wash hair after every going out session as the pollen stays on your hair, skin and clothes and you keep reacting to it over days!
Also things like not opening windows on high pollen days, wash all bedding if windows were open.
There's lots of lifestyle things to be done to make hayfever more manageable. The allergy UK website has a great page on it with tons more advice.
Stress of life (in this case exams) can cause extra rashes when the immune system is already on overdrive unfortunately.
Speak with the GP because we know hayfever causes a decrease in expected exam results!