Hidden infection in RCT tooth#46.

I have tooth pain 46 for 2 years now.Have jaw pain under ear lobe and neck on right.Went to dentist for jaw pain&spotted 46 hurts for tapping,biting pressure.xrays,CBCT scan clear.Endo told me to try RCT,did in 2020.No relief,same jaw,tooth pain.MRI, CT of jaw,neck normal.Saw another endo last year&he did partial retreat for distal root as it wasn't filled till end root tip.partial retreat last year&no relief.Went back to Endo this week and told me to extract 46 as nothing found but tooth keeps hurting always.Took CBCT&clear.He wanted to try one more retreat as last try before ext.Reopened tooth 3 days ago.One root in mesial was having wetness in old canal filling.He said it stinks and blood color changes like purplish.He put medicine inside both canals.He said he didn't see those in cbct or x-ray.Is blood color changes like purplish indicate infection?put me on antibiotics for 10days.2nd step RCT after 6wks. is this infection will spread across? do I need to remove Tooth immediately?