Oily hair & Scalp

Over the past couple of weeks I have noticed that my hair & scalp have become very,very,very oily.I haven’t changed my shampoo which is a very mild shampoo designed for babies nor have I changed my diet.My scalp is itchy to.
The only real change that I have made is that I have upped propecia from 1/4 tablet to 1/2 tablet a day.
What the hell is going on ? Any feedback would be appreciated.