I have four boys, three of which are circ'ed and one intact. My second son's circ looks similar to what you described in your son. I have left it completely alone. It will most probably resolve itself. If, at puberty, it hasn't, then we may look into consulting a urologist, but, if it doesn't inhibit normal sexual function and urination, again, we will leave it alone. And I really hadn't thought much about it until now. LOL. But, I have learned a lot from this thread.
I do regret that I circ'ed my three older sons, but, at the same time, I cannot change what happened simply because I want to assuage my guilt. I really have no guilt, as I didn't know any better at the time. My fourth son is intact and I certainly believe in the adage of "You know better, you do better."
However, I believe circumcision is a personal choice and I will not be circumcising any future sons (although I will not be having any more) and I will certainly aid my children in their quest for knowledge when they have their children. I also understand the arguments regarding that circumcision is done to someone else who is not choosing this. It does make sense.
But, you cannot undo the past and you can certainly change the future.
My hopes are the future will be changed for you. Good luck and take care.