it will come back because its collecting carbon and soot constantly.
when the message reappears that's your cue to take it on the motorway and blast heat through it to turn the carbon and soot to ash and empty it out. you do that by holding the revs at 2000rpm in 4th gear constantly while doing a few laps. it blasts tons of heat through the DPF. depending how blocked it is it could take upta 30 mins. monday morning at 4am when there's no traffic on the motorway is always a good time. nothing to get in your way. using dipetane consistantly drastically lowers dpf problems because it makes the fuel burn completely.
if you don't use a drop at every fill up the EGR, DPF, intake manifold and injectors are going to get repeatedly choked and cacked up with carbon and soot.