Its funny, you can always tell who is brand new to Malaysia, they are sweating like crazy. A newcomer will think they walked out the door and into a pot of boiling water.
I also did for about the first 2-3 years and then it gradually reduced to what is normal for any Malaysian, that is to say most of the time you will not sweat unless under physical stress like sports.
If you look around, even older people have nice skin and that comes from so much moisture in the environment. Malaysians, their skin is so soft and smooth. Im from US and there people have to use heavy moisturizers to keep hydrated skin, thats why we all have lines and look weathered. When I have been here a while and then take a trip back to US, my skin starts cracking and flaking with dryness and feels stiff until I go back to Malaysia.
There is nothing you can do to stop this, you just carry handkerchiefs until one day you get used to it. You will.
The weather is fairly consistent around the year, about 30c (90F) and only cools down a bit at night. Sometimes the nights feel worse than the day, thick and sticky. But humidity isnt always so high, right now for me its 65%, sometimes its as low as 50% and as high as 100%.
It affects my mood very much still. Cant say I ever loved hot-water rain. And I cant wear the clothes I want, I have to be conscious of the heat and wear the lightest clothes. Sometimes at night I cant sleep at all because the weather is thick and foul, even if using aircon. Sometimes I have severe headaches for three days straight and then the weather milds and softens and Im OK again.
I mentioned this once before, the biggest problem for me is that the weather tortures and ruins anything--plastic, steel, rubber. Other than glass, what here doesnt rust?? I buy airtight plastic containers and put desiccant inside and there you can store sensitive items. Leave shoes in light and air or they will become moldy.
Being close to the equator skin cancer is a high risk and probability. Dont wear shorts, stay covered up and use sun block. I can definitely tell there is damage to my skin after years here. Remember that the genes of locals have adapted over centuries, yours havent.
I never drink enough water but yes you should drink more than you probably ever drank in your life!
Though I miss seasons, it is also a good thing to be able to predict the weather. it wont be 0c, it wont be 50c. These days I hate the cold, if its 25c im already reaching for sweaters!
The good part about the weather is the plant life, fantastic plants, not like anywhere else.