Celiac block/neurolysis with 5 ml 100% alcohol only improved abdominal pain for one month before returning. does that mean it didn't work ?

Not necessarily: Why did you have the procedure? These blocks are usually reserved for severe problems with no other solution. In patients with pancreatic cancer the pain usually returns in 3 months as disease spreads. Repeating procedure only works in 30%. 5ml is a lower volume of alcohol than usual. Talk to your doctor and get a second opinion from an anesthesiologist who specializes in these type of blocks