Doctor , my child is nine years old , and I recently found that he was constantly telling lies about how he is doing at school .   Is he doing very well at school ?   He is doing OK , but he pretends he is doing much better by telling lies .   What's his problem ?   This may be complicated . But I think he may need to build up his self-esteem .   How can his he do that ?   There are a lot of ways to help a kid build up self-esteem , but to begin with , you can try and give him more rewards . Rewards will help a chil improve his self-esteem . 