@SarahGen-- RICE helps but if you have a swollen knee, elevation and ice are not going to help much unless it's done immediately after the symptoms appear. Applying ice two days after the swelling is not going to be very effective.
However, you should keep resting and elevating your leg and apply some compression. You can use something like ibuprofen to treat the inflammation and pain.
If the pain and swelling doesn't go away, you might have torn something in your knee. You need to go back to the doctor in that case. An MRI or x-ray may be required.