You might give up on your winnings by donating them to a charity. After all, most major lottery games give a portion of their profit to charities and good causes. That means you are indirectly donating even if you only buy a lotto ticket without winning anything. Many believe that makes the lottery halal.
On the other hand, some think it’s better to donate directly to the desired organization. They also think that the donation won’t justify your actions of playing the lotto. Ultimately, it again comes to your point of view.