Nasonex spray is a steroid?

Mometasone furoate monohydrate (Nasonex,) is indeed a steroid. However it is not androgenic so you won't grow a moustache!

Does nasonex raise blood pressure or lower?

I use Nasonex and I have several heart and blood pressure problems so I doubt it is causing you any trouble in that area. Any drug that is likely to cause issues with your heart would not be one.