Lixen gives good information there on checking them, and you may want to get a doctor to check too.
There are creams that have a local anaesthetic to deaden the pain, that can give some immediate relief.
What kind of cushion do you use - ROHO? Make sure the air is correct in it. If you don't have one an O cushion may take a little pressure off.
Is this from sitting too long or did you become constipated during the trip? Addressing this will be as important as anything.
I hope you get relief soon.