i had both collagen and teflex. I would suggest teflex before collagen since it is more long lasting and doesn't get absorbed. I had my injections 2002 to 2003.
My present Urologist doesn't recommend either since his experience did not show any long term benefit. He was doing it in 1997 to 2001.
Each urologist has different experience so it may not be what works for you.
The bigger question is how incontinent ( pads you use)
Have you tried bladder training with biofeedback and kegels
Other question is costs - I had heard that the bulking maybe as costly as sling or sphincter.
I just had the artificial sphincter installed and bill as outpatient (stayed to next day) was $27 to 30k. Insurance knocked down $16k off of bill before they settled.
Good luck, I messed around with the problem for 10 years before I got this fix.