M.B.
Teething in babies can occur as early as 2 weeks though it is rare. Either you or the father typically would have gotten their teeth early as well. This is a good one to write in a baby book....it will help when their child possibly begins to teeth early on too.
The size of your newborns mouth is too small for a toy, a good finger pinky is a great substitute. Just make sure to wash with soap and water, infection is of great importance this early in life. You can try offering a pacifier just for comfort, you really don't want to offer something orally if it's going to be placed in the back of the mouth. Personally, this is harder on mom's. A general rule of thumb is to use Motrin/Ibuprofin over Tylenol when you think muscle pain. You can try that in the evening to help calm her/him down after a warm sponge bath.
If ever in doubt, call your peditirican, their medical assistant can offer reassurance which is what we need to hear sometimes.
It's hard, hang in there!