you have left lat rectus palsy. since it is from childhood hence complete recovery is not possible. but you can try inj methyl cobalamine 1500 iui/m×10 and latest rectus exercise ie try to look towards the left forcibly and then squeeze your eyes for few seconds. repeat it for 10 to 15 Times a day for one minute or so. after few months you may have some relief .
Next Steps
even if you don't get relief then please learn to live with it.for that while looking towards left side you will have to turn your face instead of your eyes.