It is possible to have scarring from this but generally is not likely from a normal course and treatment from an urushiol induced rash. Some people use very harsh chemicals (such as chlorox full strength) which can promote scarring. This is injured skin and so taking care and promoting proper healing will prevent any long term scarring. Of course, I do have to say I am not a doctor but I have had experience with poison ivy rashes. I've probably had 2 dozen outbreaks over the last 20 years and only one nasty outbreak left any sort of marks but that was probably due more to skin irritation from clothing and slight infection. True story - I got a case of nasty rash on the end of my nose and on my neck (the only spots not covered up while I was pulling vines). This would be the one time it took 3 weeks for the rash to go away - boy did I look odd for awhile! I took care of the rash similar to you did and once the open sores were gone I started on a regimen to heal the skin which included putting Vitamin E oil on the spots. I've used Vitamin E oil topically for many years to promote healing and remove or reduce scarring (I'm a klutz so there is experience here :-)). I have absolutely no marks from that round of poison ivy rash. So my advice is to take care of the skin and you should be fine.