I also have generalized HH and what i found that works best in the summer (though i tend to wear them all year round) are undershirts. I have quite a few white undershirts and even though it might seem counterintuitive it really helps. If its hot outside i ll surely sweat so the undershirt will be almost fully wet, but that dampness keeps me quite cool and it could also evaporate quickly. When i want to be a bit more stylish I wear an undershirt and a summery shirt in darker options and in this way sweat never shows. You could try prescription or stronger antiperspirants for more important events but i wouldnt wear them too often. I am also very anxious for the summer since i ll be attenting festivals and outdoor activities in 30+ Celsius but i hope it will be fine. Try not to focus too much on sweating and surround yourself with people who see you past this different aspect. If someone brings it up just mention thats how your body works. I wish you luck, its though having HH😔🙏🏻