I know it's all over when a guy is very short but you can still improve your charm as much as you can.
Recently I discovered walking/standing/any body movement with decent postures can improve your charisma a lot and in extremis it can turn you into a totally different person!
On the other hand, if your posture is not normal like you have scoliosis or hunchback, you can increase your heights by adjusting your posture. So it can kill 2 birds with only 1 stone. It's very worthwhile of a try.
Here are my tips for increasing your posture:
Walking:
1.Using forces coming from your hip and prop up yourself to walk.
2.Straight your spine by imposing forces onto your back(imagine your spine can not bend into any direction anymore LOL)
3.Increase the four limbs' movement ranges to the degree that you are walking nearly like a honour guard.
4.Also don't forget keep your eyes looking forwards like you are heading to a place that you want to go.