Mark, if you get lessoning of symptoms whilst taken Methlycobalamin that fantastic, but if its repairing the damaged nerves its common to get flaring of symptoms, i found that the flaring were only short periods [they were not really terrible either] but the normal symptoms can persist for a long time but gradually over months the symptoms can get slightly less after some flaring.

Have you had a test for your b12 levels ? but anyway 5mg is a good amount to take, it will NOT hurt you, your body will store what it needs and get rid of any excess, overseas they treat PN with massive amounts per day, its a shame really that some so called medical people don't know nothing about B12 Methylcobalamin supplements, use a good multi B too but don't take it at the same time, its works better that way, if you haven't read Roses site about B12, here is the site - http://roseannster.googlepages.com/home
well worth reading,
good luck with it all anyway,
Brian