Oil Leak

I recently changed the oil in my subaru (one month ago) and I forgot that when you put the filter on you only tighten it a turn or two, I put it as tightly as I could and I realized I may have broken the seal in the filter. Now I have oil leaking out, I am not low yet, but I need to know if I can fix the filter without changing the oil. I used mobil one (the good stuff).

you could drain the oil into a clean container, change the filter and refill the engine with it…

You can just replace the filter, you only lose about a cup of oil doing that, depending on your filter size, but I’d wait to see how much oil you are loosing thru the seal first.

I would just change the filter with a new one. synthetic oil flows easier through smaller openings. Even if the leak seems small now, it may get worse and cause alot of headaches later.

As said earlier, you will lose what oil is in the filter.
I am not familir with your engine, but the oil level in the pan should be below the filter. My experience is that Subaru’s are pretty well thought out designs.