Yeap! They are very expensive as they can get... New blister
formation during the course is possible, it's just the course of
the problem and the aggressiveness of the virus.
Boosting immunity, well there are many ways, and the most common
method is to get sufficient vitamins and minerals as recommended by
the RDA (recommended daily allowance from WHO). You can get this
chart very simply by viewing in any nutritionist websites. I can't
recall all the figures. Vitamins A, C and E are thought to have
antioxidant properties whereby they fight off radical formation
from foreign microbes (which attaches themselves in the body and
starts their own metabolism through their own pathways releasing a
lot of such materials that will harm the human cell).
Other than their antioxidant properties, vitamins A and C are also
well known for their skin regeneration and maintaining skin
integrity's purposes, which by itself is the primary body defense
against any insult towards it. Vitamins B aid in neural
transmission of the body and all the millions little processes that
happens in the body too. It ensures or keep in check that the body
functions are well within it's normal range.
Vitamin K aids in blood coagulation purposes, while getting enough
macro and micronutrients such as calcium, phosphates, sodium,
potassium, zinc and iron (you can find such minerals in almost all
health food - Gardenia bread for example), and all of these aids
naturally in the smooth functioning of the cellular transports of
chemicals. Certain minerals mentioned above aids as catalyst
whereas the others acts as co-enzymes. You can find out more about
these again in a nutritionist webpage.
All the best!