What Causes Redness,bulging Of Veins And Excess Sweating In Hands?

Hi. i am an 18 year old male. i have this problem, when my arms are down these huge veins bulge all over my arms and hands! this is especially worse in hotter weather. when i raise my hands it goes away. also, people have noticed my hands are red alot, plus i get sweaty hands and feet easily. i am wondering if these problems are connected, and/or what i can do to reduce it.