Yes you have to paint it back to white. How bad could it be? I can't imagine, perhaps take a photo and we'll see see.
As for your carpet, you should find out whether the paint you used is water based or oil based: water based, use water and oil based use a paint thinner. Pour it over the spilled area and scrub it hard then use a wet vacuum to suck out the excess water. You can repeat this until the paint spill becomes lighter and lighter until it's hardly noticeable. It's almost impossible to get all paint spills out, but it should be hardly noticeable anyway.
BTW, paint spills are better cleaned when it's still wet, it's probably too late for you, but this is for the benefit of other members of this forum.