Rattlesnakes rarely bite people unless they are provoked or feel threatened.
If you do happen to get bitten by a rattlesnake you do need to get prompt medical attention by either calling 911 and getting an ambulance or get to the hospital right away.
If you have no way of getting to the hospital on your own you need to call 911 and get an ambulance on the way.
Rattlesnakes are very poisonous when they bite you and if left untreated then it can lead to death within a day or even sooner.
The rattlesnake is very venomous so do your best to avoid rattlesnakes and stay as far away from them as possible and don't provoke them and you'll usually not get bitten.