Choose Paint Edit > Layer Effect > Blur Layer or choose a brush from Paint > Effectbrush > Blur Brush and use the brush to blur paint.
To blur all unmasked paint on an image layer
To set the amount of blurring, choose Paint Edit > Layer Effect > Blur Layer ❒ to open the Blur Layer Options box, adjust the Blur Radius from 0 (no blur) to 32 (maximum blur), and click Go.
To set the amount of blurring, open the Brush Options box (for example, choose Paint > Effectbrush > Blur Brush ❒) and adjust the Blur Strength from 0 (no blur) to 32 (maximum blur).