IPhone 4 front camera won't open?

A month ago my iPhone was alright and fine working perfect and out of nowhere my from facing camera stopped working for some reason and my back camera works perfectly is there a solution to this or do I have to take it to go get it fixed? And how much would it cost to get it fixed?

Try to reset it, hold the home button down while holding the power/lock button down until the apple sign comes on, and it won't delete anything just try that.