I think this is knee-jerk posturing by Russia especially after the recent diplomatic kerfuffle about Russia talking about "revoking the independence" of Lithuania.
I think that Russia will decide that now is not the time to settle this by force. They want to win the war in Ukraine first and then deal with other matters such as this. So they may elect to wait, hoping that the sanctions will be removed. If so, there is no need to take further action as Lithuania will abide by the treaty provisions once again. If not, then they will have a lot of troops freed up with which they can threaten Lithuania. In such a case, Lithuania may elect to withdraw their enforcement of the sanctions due to the presence of a large number of Russian troops on their border.
Russia has less than zero interest in starting a second front with a country with whom they don't really even share a border, respect when that would drag NATO into the conflict. And when the war eventually ends, the sanctions will end, so there will no be no need for fighting then either.
Russia will announce its own economic sanctions against Lithuania, take some diplomatic actions to save face, but otherwise do nothing.
One issue is that Lithuania does not share a border with the Russian “mainland” but with Belarus, independent from Russia but closely aligned with Moscow. Assuming Russia has the resources to threaten or invade Lithuania, they would need to have the cooperation of Belarus.