The 3.3km addition is to the roadside Hostal Asturias.
From Jarilla you do not need to retrace your steps. Follow the N-630 and you will rejoin the camino.
The accommodation listed above includes the current STATUS of reopening after the quarantine restrictions were lifted, and pertain to 2020.
Leaving Hostel Asturias there is a much more pleasant, alternative route to Aldeanueva which avoids the main road. It is marked with royal blue arrows. Turn left out of the hostel and follow the road for <1km where there is a blue arrow pointing to the right onto a country path (it’s visible on google maps). The path continues fairly straight, past a factory ??sewage works (also visible on google maps) and eventually joins the main route just after the switchback/dog leg. Word of caution - after a few showers of rain there were some big puddles and the minor streams had become a little difficult to cross, so probably best avoided if there has been any serious rain.