I “tweaked” my groin and I’ve been self-doctoring with the things I know like icing, stretching, and reducing my work outs.  Is there a “Golden Rule” on the timing of getting professional help?

Sadly, there is no simple answer.  I agree with your home doctoring approach for the most part however there are some more serious injuries when this would not necessarily be indicated.  A minor injury should take a couple of days to resolve if it is comparable to extra exertion at the gym.  Common sense is sometimes foregone by our egos when we won’t let an injury get the best of us and we continue to train, compete or work through the pain.  Not only can this make the recovery much longer, but it can work against us as encourage muscular compensation and alignment change.  Consider a balanced hockey game with 5-on-5 until one team gets two penalties and they’re now 5-on-3.  The remaining players tighten up to the goalie, strictly playing defense.

The game’s outcome and the well being of the three remaining players depends on the time spent on defense.   While miracles happen, scoring opportunities will be typically limited in this dynamic.

So back to your original question, consider what muscles are tightening up in defense for you and how this will change the outcome of your life game as to when you seek help.  Good luck.