You could have extremly bad luck and could be telogen effluvium, will be extremly weird since you used a low dose. But , I strongly suggest you to check if father, grandfather, etc, start to bald young. Cause , in many case, what it happen, is that accutane is actually stoping male pattern baldness, and once it is stoped, after a month or so ( not during ) people see hair loss. Like if you was using minoxidil or finasteride, and then you stop it, if you have male pattern baldness, it will start to fall .
Again, could be just telogem effluvium, if is that, it should regrowth alone. Again, it is not like you was using 120mg daily for 4 month. Even, so , 60, for my opinion, it is two much. Best is to use 10 to 20mg for long period of time. The high dose is old school ( 90s ) .