Kostas

The discolored areas you see on the outermost leaf sheath does is rot and it usually indicates root rot going on if it hasnt seen cold temperatures that could have just damaged it superficially outside. It doesnt look too bad though and should fix fine if you place it in an area receiving sun and let the soil dry out a good deal before watering again. The sun should eventually dry out the rotten areas and its certainly ok to leave the dried out parts on unless too many dead layers build up that could trap too much moisture on the pseudostem beneath and cause rot with cool rainy weather. Do not water it much till warm temperatures prevail in your area as they dont use much water unless the temperature is high enough for them to grow fast. If you can,protect it from rain too till the soil dries out a lot at least once before watering it again.

__________________
''To try,is to risk failure......To not try,is to guarantee it''