Tapping could indicate a couple of things. Usually it means that your rings were starved of oil for a bit, and started wearing unevenly. You may have snagged one slightly on the exhaust port and now you're hearing the leftover damage. You may have also opened up the connecting rod bearing slightly from friction, and now you're hearing connecting rod slap.
If it's rings, you have a slight chance that it will wear back down and smooth out, but I wouldn't hold my breath. There's also a chance that a ring will snag badly and tear up the cylinder.
If it's connecting rod slap, that will likely never go away, but probably won't get much worse unless you run it out of oil again.