..anchor your thumb on top of the fret board. ..dont "push" the string using you finger only, let your wrist assist your finger, and also try to get support from other fingers. ..try to keep the index finger middle finger and the 3rd finger together while bending. .. use light guage strings .. for exercise, bend a note and then hold it, slowly release it and then bend it again quickly, then do a vibrato .. this will increase your finger strength. lemme know if you need more help
