How many drawings is a mega millions ticket good for?

Salt and Peppy has it right. You almost certainly bought your ticket for only ONE drawing. (You would have actually needed to specifically tell the clerk to give you the ticket for multiple drawings if it were going to be so. Then you would have need to PAY for each of those drawings.)

Just throw the tickets in the trash can like the hundred million other people who wasted their money, and learn from your mistake.

It's good for as many drawings as you paid for. It's up to you, when you buy the ticket, how many drawings you are getting.

1 time only you will have to buy it every time that is drawn