Hi Delphie - great question - I hope you are pleased with the results of the Dermapen so far as well as the peels.
Fillers should be fine to have during this treatment period.
I recommend an injectable hydrator such as Juvederm Hydrate which will help minimise the lines by improving the moisture levels in the skin for a fresher more youthful appearance.
Please see http://www.youtube.com/watch?v=YPHMohpgXKs&feature=plcp
for more on perioral rejuvenation and how it can benefit you - as well as a live demonstration of our team performing this treatment so you know what to expect on the day.
I hope this information helps and if you have any more queries please do not hesitate to get in touch