it could be damaged, in the future try using a bulb blower first, then go to a swab. The "lens" brush is filled with dust and crap from dusting off a lens. That was a poor choice to use on your sensor. they do make sensor brushes that are electrostatically charged. Personally i don't trust puttng any brush with bristles inside my camera body for fear a bristle my snag or fall out. that and who knows what other contanaments/dust might be on the bristles.
i would try a wet swab (follow the directions closely) make sure there is no moving air and no major dust in the room. if that doesn't fix it, you'll have to send it in to get the sensor cover replaced. which could be expensive.
also there is a thread about cleaning the sensor if youwant more in dept reading. (i'll try to find it)
camera maintenance and care