There are a number of factors to consider. Firstly your teeth look to be about the right dimension with just is a little crowding present. Making the correct diagnosis is key. A helpful photo is the "lips at rest", ie your lips just gently parted, this lets us know the if the teeth are generally well positioned in the face. If approximately 2 mm of the teeth show at rest then you could have a hyperactive upper lip, this being the case there are a number of treatment options for example botox which would be a simple but temporary fix. If a considerable amount of your teeth are exposed with your lips at rest then the height of you upper jaw could be larger than normal and jaw surgery could be required. There are many treatment options that you will need to fully understand and could involve referral to a number of dental specialists.