I'm worried. The sensor on my DSLR had a few dust spots so I finally got round to getting a blower brush to clean it (I've had the camera just over a year). After watching some YouTube videos (probably not the best place to learn in hindsight) I decided to have a go at cleaning it myself. So, following the instructions from the video, I switched the camera to cleaning mode, removed the lens and gave it a few blasts with the blower. In the video they had an arctic butterfly which they then swept over the lens. So I did the same, although the brush that I had was probably of a somewhat cheaper quality (it was a free gift with a subscription to a photography magazine). I now seem to have made the dust spots worse and when I look at the sensor I see what looks like streaks. Have I scratched the sensor filter or is this probably just grease of some sort? Would a cleaning swab be a better option or is this likely to make things worse? Am I totally screwed? Help!!