acid reflux/vommitting/nervous stomach

My 9 year old son has been vommitting for years, we found out that he has severe acid reflux and is lactose intolerant.  He is on prevacid twice a day but still throws up regularly.  We find it is mostly in the morning.  He is very active in sports but this vommitting is really starting to take it toll on him and he can't function well and doesn't want to go to parties or sleepovers because he is afraid of getting sick.  

Anyone elses child have this, any suggestions, diagnosis, medications that you have found helps.  I'm wondering if there are other test that should be run.  We have done they typical, cut out carbonated beverages, dairy, acidic foods, large meals...

He has had a stomach emptying scan done and it's fine as well as an Endoscopy and it showed scaring in the stomach.  

I feel so bad for him and it's not good for his body to be throwing up all the time.

Any suggestions would be wonderful.  

[mammo]

The Prevacid isn't helping your son, you need to take him back to the doctor and let him know this.  There are other medications they can try, and don't hesitate to get a second or third opinion from a Pediatric Gastroenterologist.  I feel so bad for your son and know this is very hard on him. I wish you both all the best and hopefully you can get some answers for your son.