On the violin, the little finger is used to extend your reach and play notes that would be otherwise impossible to reach with the other three fingers. It also helps to provide support and stability to your hand position. Without a little finger, you would have to make significant technical adjustments to your playing, and you would likely find it difficult to play many standard pieces of music.
On the guitar, the little finger is used to add color and texture to your playing by providing additional notes and creating harmony. It is also used to create vibrato, a technique that involves slightly bending and releasing a string to create a vibrato effect. Without a little finger, you would have limited options for adding variation to your playing and creating expressive melodies.
Overall, it would be very difficult to play the violin and guitar at a high level without a little finger on your left hand. While it is possible to develop alternative techniques to compensate for the loss of your finger, it would take significant practice and dedication. If you have recently lost your little finger and are interested in continuing to play the violin and guitar, it is recommended to consult with a qualified music teacher or therapist to explore your options and develop strategies to overcome this challenge.