Weak erections. First week on finasteride

[Veyron]

I'm new here and apologize if I'm in the wrong place. I don't usually post on forums. My dermatologist started me on finasteride about 2 weeks ago for my receding hairline. On day 2 I noticed some testicular pain and a weaker erection than usual. Within the first week the pain went away but my erections are still weak and hard to maintain. Will this improve with time or do I need to stop the medication? I can live with the way it is now if it means keeping my hair but I certainly don't want it to get more difficult to get an erection.