Your badger may have been wandering further from home than usual in search of food. Worms are once of their main diet sources and the drought has meant that these are much deepr in the soil than usual, so your badger could be starving and and thus having to search much further afield for something to eat.
If you want to encourage it back you could try putting out some meat based tinned cat food, although there's no guarantee that some local cat might not get to it first.
A couple of years ago in the drought we had the magic experience of a couple of albino badgers pay us noctural visits for several nights, but haven't seen them since, possibly because all our neighbours have blocked up the holes in their fences which they broke down to reach as far as our garden.
Your badger will probably have come from a set where the countryside was more open which suggests it was probably desperate for food as I'm nos sure that they wander too far from home if food is normally in plentiful supply.