There are two parts to Byzantine border expansion during the First Crusade. There are the parts that were directly returned to Byzantium as part of the Crusade and there were conquests made by the Byzantines that were made possible as a result of the Crusade. I'm going to cover the latter example first since it's actually the simpler of the two.

Essentially Emperor Alexios Komnenos was able to retake several cities and citadels, as well as the land around them, as the Crusaders marched through Turkish lands in what is now Turkey. Two major factors made this possible: the Crusader victory at Dorylaeum was disastrous for Kilij Arslan and his forces. In the wake of a defeat it took time for a medieval ruler to assemble a new army and the Crusader victory threw the region into chaos, which Alexios was able to capitalize on. The second factor helping Alexios was the presence of the Crusader army. The Turks didn't know exactly what the goal of the army was as they marched along the southern coast. At any moment the army could have turned inland towards a Turkish city, or so they thought. This made Kilij Arslan and other leaders unwilling to commit an army to fight Alexios' much smaller forces as they were taking cities and fortresses in western Anatolia. They feared committing their forces to fight Alexios only to find out that the Crusaders were heading for a more important city (Mosul for example) and found it easier to just let Alexios take the less important territory. in the end, obviously, the Crusaders didn't turn inland and instead continued onto Antioch but by then Alexios had expanded Byzantine territory significantly and built a buffer between Constantinople and Turkish territory.

The matter of lands returned by the Crusaders is more complex. Nicaea was taken with Crusader help and essentially returned to the Empire, even if Alexios arranged the city's surrender himself. Antioch and Edessa present two much more complicated territories. Antioch was notoriously not returned to the Empire upon being taken by the Crusaders. Bohemond, who took the city with aid of treachery from within, argued that Alexios had violated his promise to help the Crusaders so the oath to return all previously Byzantine land was void. Many Crusaders disagreed with this interpretation (most notably Raymond of Toulouse) but Bohemond kept the city nonetheless. In the wake of the First Crusade Bohemond launched an invasion of Byzantium with an army of European Crusaders he recruited while touring through the continent. The invasion, launched in 1107, was a disastrous failure and Alexios crushed Bohemond's army and forced Bohemond to agree to Byzantine overlordship of Antioch. Bohemond was declared Imperial Governor of the city since Alexios knew that he could not impose his rule directly without Bohemond's aid. Another condition of this agreement was the appointment of a Greek priest as Patriarch of Antioch. Bohemond died without ever returning to Antioch and disputes over the extent of Byzantine overlordship over Antioch continued for pretty much the entire life of the Crusader States. Byzantine sort of rules over Antioch, but their practical influence was often pretty negligible.

Baldwin, future king of Jerusalem, took Edessa during the course of the First Crusade. He and some fellow knights went on a diversion to the city which was controlled by Armenian Christians and managed to get himself appointed ruler of the City during his stay there. Edessa later became the County of Edessa, part of the Crusader States. Traditional Crusade scholarship has seen this as Baldwin seizing territory for himself and making a new life at the cost of local Christians. However, Peter Frankopan has recently argued that Baldwin was actually taking over an Imperial position and was generally very cooperative with Byzantine policy, effectively ruling the city as an Imperial Governor including taking on the clothes and style of the Eastern Empire. In this light, it looks more like Baldwin was helping to secure a Byzantine territory against encroachment by Islamic forces rather than usurping it from Byzantium for his own use. Frankopan doesn't cover how Edessa's relationship with Byzantium changed when Baldwin left to become King of Jerusalem in 1100, though. Practical Byzantine influence over Edessa would have been pretty minor but it certainly never had the same level of difficulty as with Antioch so it's possible they were generally more cooperative, and allowed more freedom as a result. Edessa was the first major Crusader State to fall to Islam, Zengi took it in the 1140s.

Peter Frankopan's The First Crusade: Call from the East is the book that probably covers Byzantium's gains in the best detail. It's not the best introductory history to the subject, though, and only covers the First Crusade (duh..) Thomas Asbridges' The Crusades is a great general history especially on the Crusader States period from 1099-1187.