I rammed my head quite hard on the left side into the corner of a kitchen cabinet last night. It swelled almost to a tennis ball size rather rapidly. I iced it for several hours and it reduced in size. Today it is discolored and there is a 2 inch indentation above my eyebrow that is possibly caused by the swelling above it. Outside of feeling tired today and the right side of my face feeling a little numb, there does not seem to be any other residual damage. What I want to know what signs should I be aware of that might indicate a concussion?