Entanglement has nothing to do with hypothetical wormholes.
Elementary particles don't have a size, and the size of composite particles has nothing to do with either entanglement or wormholes.
The OP may be referring to some of the video lectures made by Leonard Susskind in which he talks about forming ER bridges between black holes. I'm not sure if this counts as a peer reviewed source or not but I believe this may be what he is referring to.