You can reduce by exercising and proper diet, don't be tensed just eat with concentrating on the food you eat do not concentrate on T.V or anything like that. Exercise twice a day properly. It will help you.
Bruises after surgery disappear after surgery usually. I agree with above, I hope you are healing nicely. Definitely do give us some after pics when you are all healed. waiting for your improved image.
For a normal person 8 glass of water is enough to be hydrated, you must consult your doctor they will better suggest you that how much water is good for you before surgery as it all depends on person to person(before surgery).