If you are experiencing low self-esteem due to losing your hair from a bad skin allergy, the best approach to improve your self-concept would be:
A) Focus on your strengths and your positives.
This approach encourages you to recognize and appreciate your qualities, skills, and attributes that make you unique and valuable, which can help boost your self-esteem.
While building relationships with high self-esteem individuals (B) can be beneficial, it is not as direct as focusing on your own strengths. Ignoring what others think (C) can help, but it might be challenging to implement effectively. Telling others negative things about yourself (D) can reinforce your low self-esteem rather than improve it.
In summary, focusing on your strengths and positives is the most effective way to improve your self-concept in this situation.