That's pretty tough.
In the end, situations only have as much power over us as we give them. When someone laughs or alienates us in some way, the natural reaction can be to give in, feel shame and show it, etc.
However, if it doesn't appear to bother you, it should go away. Not at first and not quickly. However, laughing with it can help...being prepared and making light of it.
If it does come up, you could blow it off...laugh along with it, shake hands and apologize to the person. Be friendly (it's hard for most people to continue being a jerk in that scenario).
Then, in private, you would explain things to your brother.
In the end, things happen to everyone in our lives...we all go through events (if you live long enough) that can be troubling, shaming, embarrassing, etc. By your brother seeing this and understanding this truth from you, it might provide him more strength as well.
When those who look up to us see our faults, there does tend to be a disappointment, but it also opens the door to strengthen those relationships with more than the self-delusions we tend to create for people we love.
That's all a lot of talk and just my opinion, but hope it helps