If a trader is having a open position and market went against of the position, then definitely trader is facing some loss ( although in real as the position has not closed so it is not the actual loss).
In my case I keep the position open and if I find a good support at certain level then only I do add ( which is called the averaging method) but there is no fixed PIP to decide, as some time I average after 30 PIP and some time till 100 PIP.