what am I doing wrong?

Question
Hi,
I am a 53 female, bowl on one league a week, 160 average, bowl with 12lb. drilled conventional. I tried fingertip one time and I wound up with tennis elbow. Can't go to 14lb. because of my back. I feel I'm in a slump. I bowl with 12lb. Wrath XP. I adjust on the lanes. The house I bowl at has medium/heavy oil. Thanks

Answer
Developing tennis elbow is caused by two thing.  Over-rotating during the release or squeezing the ball to hold on to it.  If you tried the fingertip, and it was drilled incorrectly, you would have had to squeeze the ball to hold on to it.
Without being able to watch you bowl, I cant offer any insight on what you are doing wrong, if anything.  I sugges findind a coach locally that can work with you.

If you can go with a heavier ball without injury, you will be able to increase pin action.  

Good luck,
Chip