Hi Carrie, and welcome to Kiva Friends.
As far as I know, the only way to contact your borrower is to click on the link to her loan page, scroll down to the bottom and just above the repayment schedule you will find a link to "comment on this entry".
This comment then can be read by BRAC South Sudan, the microfinance organization that is partnered with Kiva to lend to this person. I don't know what the chances are that they will be able to pass on the message, but you could at least get close.
I usually make comments here when loans are funded and thank the organization for allowing us to help fund this particular loan and wish the borrower good health but I'm not sure how much time they have for reading messages
enjoy your lending and *know* you are making a difference...

-jan-