If it's tight and you don't hear anything,AND had your mech looked at it then yeah,run it.I just answered what you asked and didn't elaborate.Probably should have added if it's not noisy or loose,then it may have just leaked some grease.It shouldn't do that but it can happen,Keep in mind rips/cracks in the boot can be hard to find,the clamps might slip and let greas out also...
I don't want to get you into unneccessary work,if you say the shaft is ok, it's ok.
Now,you can get a little more grease back in there,I used a grease needle and injected some high quality grease in mine and bought some time before I replaced it.Another idea,Autozone sells 2 types of replacement boots also.Both come with clamps and grease.One is a solid oem type,pull the shaft,replace the boot and grease and put it back together.The other is a two piece,more of a universal type,that glues together so you don't need to remove the shaft.The glue chem welds it together,supposedly....Anyway,If you think your ok,just use a small grease gun and needle to replace what got out and look it over again really close,check the clamps really well,they might have slipped a little and just let some out...

 

That is what I am hoping really, that it just slipped and let some grease out while I was at full lock or something and then it splattered everywhere while I was drive there after.
I should crawl under and whip it all out but I haven't had the time quite yet. I may just check the clamps again and put more grease in...Ill have to get pics of it though and show you guys