Question about Elite Screens Manual

On our Screen, there was a dead mosquito (squashed when the screen was rolled up). I did not think too much and just wiped it away with a damped cloth. Now there is a stain on the screen - it looks as if the area, that go wet, is now less reflective than before. Is there any way to fix this? (Some kind of spray to apply, for example?). Thanks for any hints on this.