I've finally found some time to read this chapter -- nice one, CJ!
I've never been that observant. In hindsight there were definitely hints, but if his self-esteem was that bad I would have expected a few more blatant hints -- like getting more upset than he was when Steve originally tricked him into wearing speedoes at a party. Some of it could be argued that as a swimmer he was used to it, but there's a big difference between a sporting event and a social event.
Having said that, everyone is an individual so there is nothing wrong with an atypical reaction to selected situations.
One thing I'm expecting is that Chris will still have times when he's self-conscious. If the lack of self-esteem was that ingrained, I would expect that it would take some time for him to get over it. He's made some progress and taken probably the biggest step, but a complete change without some backsliding is probably too much to expect.
Even though I have a previous chapter didn't have a lot happening, I have to disagree with you on this one. There was little in terms of the overall story plot (just the data stick plan), but there was a lot of character development and that's just as important to a story. A slight pause before things pick up again (eg. when Eric gets home) is good for the readers.