Can an upper gi series xray cause any damage?

Not the x-rays: X-ray exposure poses a lifetime cumulative risk for illness. Single exposures to diagnostic (as opposed to therapeutic x-ray) are not harmful. Modern x-ray equipment is more efficient and imaging techniques are becoming more refined, resulting in less x-ray exposure per procedure.

Nothing: beyond the minimal theoretical risk of any diagnostic xray

No: I.t does not cause any appreciable damage with the small amount of radiation