Nyoox

Hey, So after getting my 5th badge in sinnoh I found that I am supposed to go back into Jubilife City. However after making my only pokemon who knew smash rock forget that move earlier and having no way of getting back into the firsts towns without that move Im now stuck. I've been trying going to the move relearner but It didnt help. The HM learner is at Oreburgh City if I remember but I cannot go there either. What should i do?