The elbow isn't meant for pitching. 2 of my 3 sons had Tommy John surgery, many years apart. So, I know far more than I ever wanted to know about elbow issues. When I played in the dark ages...it hurt when I pitched...when the pain became too much, I moved to second base in college! Times have changed.
My sons both reported popping in the elbow before they wound up needing surgery. They both felt pops the closer they got to needing surgery. And, they both pitched through the pops and stuff. So, you're not dealing with a dad of a couple pansies. My oldest heard the pop and had torn up his pitching elbow as a junior in college. He knew he was done for a good long time, but the pain was manageable and he wasn't a big league prospect...so he pitched and won 4 starts AFTER he knew he had a serious elbow problem. As long as he had enough stability to throw strikes...he pitched. (When you lose it and the ulnar ligament no longer stabilizes your elbow...you lose command and velocity. He lost velocity, but it wasn't until the command left that he knew he had to have surgery.)
My youngest son was a big-time D1 prospect and potential draftable lefty. He pitched for YEARS hearing pops...he pitched knowing it really hurt. He went to an top ortho and got the best care. He heard pops and his doctor said, "If you weren't 15 years old, I'd do surgery right now. But, the ligament CAN heal. And, surgery isn't the first option...ever." So he'd rest and rehab and be fine for awhile. If he'd stopped and REALLY addressed things when he FIRST heard popping, he might've saved his elbow.
You look for excuses to keep pitching. It only pops once...it felt OK after the 2nd inning, etc. I did. You did. My sons did. But...your elbow is NEVER supposed to pop. Ever.
So...rather than wind up having TJ surgery like my sons...go have it checked. They can do an MRI and X-rays and tell you if you ulnar collateral ligament is solid. If it's not, they can tell you if you're headed for problems.