Endoscopy biopsy: distal esophagus esophageal squamous mucosa showing reactive change, negative for barrett's esophagus or dysplasia. there are no histological features of eosinophilie esophagitis. changes non specific. is this concerning?

No, this pathologic finding is commonly seen in patients with GERD. You have nothing to concern, just focus on the treatment of GERD. Take care.

Those changes do not seem significant, but the only person that can interpret them properly is the person who did the biopsy itself. You should refer back to the gastroenterologist who took the samples. Good luck.