I recommend AHC mask packs.

It is the famous AHC mask pack.

I stocked up on this when it was sold in large quantities at a low price on a home shopping channel a while ago, and I've been using it continuously lately. It's great for cooling and soothing the skin in this sweltering heat, and its moisturizing power is excellent; I can definitely feel that the hydration lasts a long time after using the mask. I think it's really good value for the price.