Albert Barnes on Galatians 1:21

Afterwards I came, etc. In this account he has omitted a circumstance recorded by Luke, Acts 9:29 of the controversy which he had with the Grecians or Hellenists, It was not material to the purpose which he has here in view, which is to state that he was not indebted to the apostles for his knowledge of the doctrines of Christianity. He therefore merely states that he left Jerusalem soon after he went there, and travelled to other places.

The regions of Syria. Syria was between Jerusalem and Cilicia. Antioch was the capital of Syria, and in that city and the adjacent places he spent considerable time. Comp. Acts 15:23,41.

Cilicia. This was a province of Asia Minor, of which Tarsus, the native place of Paul, was the capital. Acts 6:9.

(c) "I came" Acts 9:30