Reddening of skin with small bubbles.

Doctor, I have a problem with my leg. I used to drink water during lunch,dinner , the matter is if i do not take extra 2/3 glass of water then the color of skin around the ankle portion of my leg becomes red and with in minutes tiny bubbles will form with minute pain and sometimes during night at bed i unknowingly will scratch it and as a result it will spread all over between knee and ankle I'm experiencing this for the past two and a half years . I have consulted so many doctors including skin specialist some of them are saying it's because of weather change or lack of quantity of water in my body. If they were right I have completed my Bachelors degree in tamil nadu one of the hottest state's .During that time i have skipped water during lunch time for so many days BUT I DIDN'T EXPERIENCED this problem for the entire 4 years there. But I started to face this problem when I went back to my home in kerala. If I drink a lot of water then no problem, no one in my family has this