If A shames B and causes shame and public humiliation what is the correct approach? Should B approach A and tell him of his feelings? Even if B feels that he will never be moichel A for all the pain, as it is impossible for A to put things right? Apparently the Magen Avraham says that B should approach A and ask lama asisi kach vkach. For what reason? What is the eitzah in such a case?
The Magen Avraham is based on the Rambam Hilchos Daos 6-6, that when someone hurts us we shouldn’t keep the feeling inside and let the hatred stew inside of us, rather we should discuss it with the person, and try to come to an understanding together with them of what happened. Very often what happened was because of some misunderstanding, and when the person is approached and asked why they acted that way, they will either realize that they did something wrong and apologize, or they might explain themselves, and the hurt person will realize that the other person didn’t mean to hurt them. In any case it will help make peace in klal yisroel, and prevent the hurt person from hating the other one. This is what the torah tells us Vayikra 19-15, “Don’t hate your brother in your heart, you should rebuke him, but don’t insult him when you do it” Rambam ibid 6-8.
This rule however does not apply all the time, and there are times when it is better not to approach the other person. For example, if someone slights us and we can shrug it off and get over it without discussing it, that is better. However if the negative feeling is too strong to overcome by ourselves then we should approach them.
Your case seems like the hurt is not in this category, therefore the recommended approach is to speak to the other person, (or give to the other person the message that you were hurt, to give them a chance to talk about what happened). However before you approach the other person you have to be in a frame of mind that you will be able to discuss the matter with them in a objective manner and not just in order to voice your point. This is not so easy, and it can only be done, if at all, after you have calmed down.
There are some more points to this, and I am attaching some notes that will include the other things you will need to know. Please see the following link Lo Tisna 5768
Mitzvas Halevavos Hilchos Ahavas Yisroel -18, Also see Rashi, Metzodos, and Gra on Mishlei 17-9,