Sometimes accidents happen. In a 20th century oil painting an impact damage from the front resulted in a large and complex tear. The canvas threads were realigned and the tear mended.
Once the tear was mended, the gaps resulting from paint loss around the tear were filled with a reversible putty and retouched in order to disguise the tear.
Detail of the tear after filling and before retouching 
Detail of the tear after treatment
Sarah Bayliss Conservation 