Why does propecia cause water retention in face? Does this go away with continued use?

Hi Docs, I have been on propecia for only 2 and a half weeks and about 10 days in I noticed my face looked bloated. When I would wake up in the morning my cheeks felt heavy and when I would press my thumb into them it would leave an imprint for several seconds. It was evident I was retaining water. Is this a side effect from the elevated estrogen?Is there anyway to rid this water retention and stay on propecia? i am a lean guy who eats very little sodium.