I don't have acne, so I don't have anything to contribute to that area, BUT I've had eczema ever since I was young, so I've got some tips on that! These tips are what worked for me, but they may not have the same result on you since everyone is different.
- if the eczema on your arms/legs/body is really severe, don't use soap. You might think this is really dirty, but really, the less chemicals/stuff in general on you the better. Just use water and rinse yourself thoroughly.
- this is gonna sound real dumb but seriously DO YOUR BEST to just not scratch. AT ALL.
- some sweat tends to gather at your elbows, armpits, and behind the knees, especially when you're sitting for long periods. Make sure you regularly gently wipe those areas dry so that it won't build up and irritate your skin.
Lastly, I suddenly got very bad eczema on my hands about 4 years ago. It was really embarrassing since I live in a tropical country and can't cover it with gloves or anything. I tried to do a lot of stuff and slathered on loads of creams but they all didn't work. The only thing that worked for me is this cream from Derma E called Psorzema Creme. I ordered it off iHerb, which means it's really cheap and made with natural ingredients.
I'd apply the cream on all the parts that are dry/itchy, then to "seal" it I use The Body Shop's Vitamin E Aqua Boost Sorbet over it too. It works really well, my hands are back to normal now and I even have hair growing back on my fingers because last time I would scratch so much they wouldn't grow (YES it's disgusting).
It might not work for you, I know this cream has had some 1 star reviews because it didn't work for them. But it's a cheap and natural option so why not try it out! Fair warning: it doesn't smell pretty. A bit like old saliva from the back of your throat. Another reason for me to put the Aqua Boost Sorbet over it.