My 2 1/2 Yr Old Grandson Had A Scab On

My 2 1/2 yr old grandson had a scab on his thumb for a couple days but now the scab is gone and it is swollen and red. Does not have a pus bump but looks more like a tiny crater. Is a warm water soak with a little salt enough or should we pu neosporin and a bandaid on it?