Architecture for large database for score system

I have a system where people can play online games and collect points. I also need a history, that i can manually can make some points undone. That is why I cant just have one row for one user and add the points every time. I need a kind of history and I think also a table where I add all points for each user. The problem is that there will be a lot of points. Maybe there will be some (or a lot) million rows each day... Maybe 50 Million per day. How can I make this with mysql. I think i also will merge data after a period of time to delete rows, but i still will have Millions, or hundrets of millions rows.