doubt you've taken enough creatine to fuck with your kidneys that severely. how often do you measure BP? did you do the reading at home or was it done at the doctor's office?
if at home, take it again in the morning, right after you wake up. get up and pee if you have to go and then go back to bed and lie down for five minutes or so before taking it. 161/90 is high but it's not at danger level for someone your age unless it becomes chronic. about six years ago i got measured at like 150/90 at the doctor, repeated on a few visits. she freaked out a little and ordered lots more tests and shit: x-rays, MRI. then i left for chile and spent a whole year taking my own measurements like every two or three days. it was consistently 138/85 or so, which is still way too high.
but then i got back, went back to the doc, and my BP was 120/70. five years later, got it measured last week when i went in for being sick and it was 122/80. so it was just a false alarm.
TLDR: don't worry yet.