well after this years performance it'll probably be the last time it's opened to visitors overnight. i purposely got there after the celebrations and was told it had been horrendous all night and not too many folk had turned up.
in regarding the damage done to the stone itself i would say it isn't superficial, i hope i'm wrong. as you go in you walk to your left hand side up towards the alter stone or equator stones,it's on one of the tall ones nearby.