Using an FM2 (at 10th exposure) and cap on the lens, I accidentally press the shutter release. This create a blank shot.
Is there a way I can reuse that frame, if the counter is now at 11th frame?
No. After you advance the film, you can't re-expose a previous frame on a Nikon FM2. the inaccuracy of the film advance mechanism plus the uncertainty of the position of initial starting point makes this a nearly impossible, as Alan Marcus points out.
If you don't advance the film on a FM2 after an accidental exposure with the lens cap on, you can use the double exposure feature of the camera to re-expose the same (unlit) frame.
To do this, pull the multiple exposure lever (1) in the direction of the arrow shown in the photo, as you wind the film advance lever fully (2). The frame counter will not advance; only the shutter is ready to be released again. Although the finger pulling the multiple exposure lever will automatically slip off the lever as the film advance lever is wound, multiple exposure operation will have been performed correctly.
After winding the film advance lever fully, you can take a new shot, illuminating the same frame on the film again.
Note that this assumes that the cap on the lens or the viewfinder did not leak any light on the film during the first exposure. This is especially an issue of the camera is set to (semi-)automatic exposure. The lens cap will cause a long exposure, increasing the risk is light leaks. Otherwise you'll end up with some light artefacts on your final image. (Thanks to Michael C to mention the risk of light leaks through the viewfinder).
Sorry to report that the inaccuracy of the film advance mechanism plus the uncertainty of the position of initial starting point makes this a nearly impossible task. If you rewound the film back into the cassette and attempted to reposition the unexposed frame for a retake, most likely an adjacent frame would be double exposed. Best advice is to let this unexposed frame alone.