It should be noted that what is going on in Belarus is not an east-west thing as it is in Ukraine
The opposition in Belarus is pro-Russian or at least not anti-Russian. What is going on there is more an intramural affair. And the Russians seem to be taking a hands off attitude.
Having said that, I can't help but think that Putin is experiencing a degree of discomfort seeing people in a neighboring country rise up against sham elections and election fraud.