First, the caveat. It’s difficult to make an accurate diagnosis based on just one photo, even a good one like this. So, consider this as a suggestion for what it might be, not an absolute identification of the problem.
You didn’t indicate where you are located, but being a live oak tells me you’re in the southern part of the country. From the photo and your description, it looks like it is oak leaf blister disease. This is caused by a fungus, Taphrina caerulescens. It infects leaves just as they break from the buds; older leaves are usually not affected as much. It causes distortions of the new growth, and in some cases may cause some localized overgrowth. This all fits your description.
There is no treatment or cure. The trees can be reinfected each spring. Fungicide sprays can be applied just before budbreak, but efficacy may be sporadic. The good news is that it won’t kill the tree, and usually doesn’t cause it any significant harm. It just doesn’t look good.
Here’s more information. Also try a search on the scientific name.
Oak leaf blister
Russ Carlson, RCA, BCMA
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