An unsafe lane change is considered a moving violation, and like all moving violations, this means you are going to get points on your license. The unsafe lane change points may vary depending on the specific nature of the offense you have committed and on where you live, but normally you can expect to get either two or three points for an unsafe lane change.
Getting points on your license can cause you a number of different problems. First, points can make your car insurance rates go up, because the insurer is going to see that you have broken traffic laws and determine that this makes you a riskier driver. Second, if you get too many points on your drivers license within a specified frame of time, all of those points will be added up and your drivers license can be suspended or revoked by the DMV in your state. Third, if you want to do something that requires a clean driving record- like getting a commercial drivers license or a job that requires you to drive regularly- you may be disqualified from doing so because of the points on your license.
As such, if you get a ticket for an unsafe lane change, you may wish to explore potential defenses available to you to fight the ticket or you may wish to attempt to arrange a plea bargain agreement wherein you attend traffic school and don't get any points on your license. To have the best chances of doing either of these things, it is in your best interests to consult with a lawyer.