My surgeries aren't getting completed. The doctor pawn just keeps doing them over and over to the same patient and nothing happens. It says that he's standing and then operating, then he goes to another task and then attempts surgery again. All I'm trying to do is swap out a peg leg for a prosthetic leg. It gives the following error:

JobDriver threw exception in initAction for pawn Golf driver=JobDriver_DoBill (toilIndex=12) driver.job=(DoBill (Job_2612816) A=Thing_LynxMan263085 B=Thing_MedicineHerbal303867 C=(215, 0, 84)) lastJobGiver=RimWorld.JobGiver_Work
System.NullReferenceException: Object reference not set to an instance of an object
at FacialStuff.PawnExtensions.CheckFaceForAddedParts (Verse.Hediff,FacialStuff.CompFace,Verse.BodyPartRecord,Verse.BodyPartRecord,Verse.BodyPartRecord) <0x00020>
at FacialStuff.PawnExtensions.CheckPart (System.Collections.Generic.List`1<Verse.BodyPartRecord>,Verse.Hediff,FacialStuff.CompFace,FacialStuff.CompBodyAnimator,bool) <0x00572>
at FacialStuff.PawnExtensions.CheckForAddedOrMissingParts (Verse.Pawn) <0x0053d>
at FacialStuff.Harmony.HarmonyPatchesFS.ResolveAllGraphics_Postfix (Verse.PawnGraphicSet) <0x0004d>
at (wrapper dynamic-method) Verse.PawnGraphicSet.ResolveAllGraphics_Patch2 (object) <0x006c8>
at AlienRace.HarmonyPatches.CheckForStateChangePostfix (Verse.Pawn_HealthTracker) <0x00102>
at (wrapper dynamic-method) Verse.Pawn_HealthTracker.CheckForStateChange_Patch1 (object,System.Nullable`1<Verse.DamageInfo>,Verse.Hediff) <0x008ab>
at Verse.Pawn_HealthTracker.AddHediff (Verse.Hediff,Verse.BodyPartRecord,System.Nullable`1<Verse.DamageInfo>,Verse.DamageWorker/DamageResult) <0x000c8>
at Verse.Pawn_HealthTracker.AddHediff (Verse.HediffDef,Verse.BodyPartRecord,System.Nullable`1<Verse.DamageInfo>,Verse.DamageWorker/DamageResult) <0x0007e>
at Verse.HealthUtility.TryAnesthetize (Verse.Pawn) <0x0012f>
at RimWorld.Bill_Medical.Notify_DoBillStarted (Verse.Pawn) <0x0009c>
at Verse.AI.Toils_Recipe/<DoRecipeWork>c__AnonStorey1.<>m__0 () <0x001c3>
at Verse.AI.JobDriver.TryActuallyStartNextToil () <0x0071f>

Verse.Log:Error(String, Boolean)
Verse.AI.JobUtility:TryStartErrorRecoverJob(Pawn, String, Exception, JobDriver)
Verse.AI.JobDriver:TryActuallyStartNextToil()
Verse.AI.JobDriver:ReadyForNextToil()
Verse.AI.JobDriver:TryActuallyStartNextToil()
Verse.AI.JobDriver:ReadyForNextToil()
Verse.AI.JobDriver:Notify_PatherArrived()
Verse.AI.Pawn_PathFollower:PatherArrived()
Verse.AI.Pawn_PathFollower:StartPath(LocalTargetInfo, PathEndMode)
Verse.AI.<GotoThing>c__AnonStorey0:<>m__0()
Verse.AI.JobDriver:TryActuallyStartNextToil()
Verse.AI.JobDriver:ReadyForNextToil()
Verse.AI.JobDriver:TryActuallyStartNextToil()
Verse.AI.JobDriver:ReadyForNextToil()
Verse.AI.JobDriver:TryActuallyStartNextToil()
Verse.AI.JobDriver:ReadyForNextToil()
Verse.AI.JobDriver:TryActuallyStartNextToil()
Verse.AI.JobDriver:ReadyForNextToil()
Verse.AI.JobDriver:Notify_PatherArrived()
Verse.AI.Pawn_PathFollower:PatherArrived()
Verse.AI.Pawn_PathFollower:TryEnterNextPathCell()
Verse.AI.Pawn_PathFollower:PatherTick()
Verse.Pawn:Tick_Patch1(Object)
Verse.TickList:Tick()
Verse.TickManager:DoSingleTick()
Verse.TickManager:TickManagerUpdate()
Verse.Game:UpdatePlay()
Verse.Root_Play:Update()