Another hyperhidrosis sufferer here.

For me I use this antiperspirant called Driclor. It's really effective as apparently it says the effect stays for days, not hours. But I try not to rely too much on it and instead I do regular jogging + exercise (seems unrelated but it does help in a way). There are times of embarrassment when I have to shake hands with people so I just put on a smile and go, "Oh, my palms are really sweaty. I hope you understand."

As for exams, I just bring a mini handkerchief with me. I remember sitting for my SPM and having the handkerchief accompany me throughout the entire time, and I felt alright.

Last but not least, try not to think too much of having it! When it slips out of your mind you would slowly yet surely come to notice your palms getting drier. I'm serious!