Don't spray sanitiser in your mouth.
Just adhere to the current guidance and keep your distance from others.
The reason you're cleaning your hands is due to the amount of surfaces they touch when outside (supermarket trolleys, post boxes, you name it..), which others may have contaminated.
Your mouth shouldn't be the same unless you're licking those surfaces.
Keep 6-8ft (2 meters) away from other people at all times.
Don't put your hands near your mouth until after you've been home and washed them thoroughly.
Bottom line - Keep your hands away from your mouth when outside, and stay 2 meters away from others.. Then clean your hands when you get inside... and you'll be fine.