Of course Judge was not hurt in this fight, Sanji didn't even tried to hurt him. The only time when we saw Sanji going on the offense was on that first kick Judge blocked, and even then it was just a regular kick, no Diable Jambe, no Haki, no nothing, it was pretty much the weakest kick Sanji can throw. The only time Sanji used Haki was to block an attack. The same thing with Diable Jambe.
Judge, on the other hand, was on the offensive the whole time. He was just doing one attack after the other while Sanji was just there defending his moves. I agree that Judge was probably holding back because he wasn't going for the kill, but compared to that, Sanji was not even trying to fight back. If anything, this chapter shows Sanji was still trying to find his resolve to actually hurt his father, he was convincing himself that he should hate that man, but the second he found that resolve some random guys jumped in the mix.
Sanji is one of the good guys, one of the main characters. Doesn't matter how terrible of a father/person Judge is, I can't see Oda letting one of the SH beat their parents. If he can't make Sanji subdue Judge by strength, I think he just did the one thing he could to make obvious how clearly stronger Sanji is by making him block the attacks just like that and not take damage from the ones that connected while all the time he wasn't even focusing on the fight but thinking about the past.
Honestly, I can't see Oda trying to make Judge into this really strong guy. I mean, just compare his introduction to the one of his older kids (who still hasn't being completely introduced) and you can see how his was lacking, it didn't had any build up, any epicness (?) behind it, nothing to say "look how impressive this guy is"… it was just a secondary character being introduced. His introduction was just like Gotti's from the Firetank Pirates.
I may be sounding like a broken record now, but it is pretty obvious to me that Judge is not supposed to be the strongest guy in Germa 66. The two old boys are the ones who will fill the role, I wouldn't be surprised if even Reiju and Yonji surpassed Judge by now and he is actually the weakest in the family. From the looks of it, I can Oda going for Shoji/Ichiji and Niji planning a coup to overthrow their father (maybe with BM's help).