Keeping your embarrassment to yourself can actually increase your insecurity. In fact, remaining tight-lipped may lead to feelings of shame that there's something seriously flawed about you as a person. Sharing your embarrassment with someone else may help you to shake its grip.
A trusted friend is a great place to start. Ask for her advice about something (people love being asked for advice!). When the two of you talk, explain that you're having trouble with an embarrassing situation; tell her what that situation is and how it adversely affects your life. Ask if the friend has any advice about what steps she might take to ease the embarrassment. Sometimes your pals have unique perspectives. A good friend can validate your feelings and at the same time help you gain perspective on whatever flaw is causing you embarrassment. Most likely it's not noticeable as you think.