Disappointed Botox Didn't Last the Way It Should

Why did I do it?  I'm 39 and have always felt reasonably good about the aging process to-date.  Then I caught a glimpse of my forehead while I was in mid-conversation (and therefore in normal facial expression-mode), and in the unflattering overhead light I saw every ridge, every line stand out like a mountain range. It aged me instantly by at least 10 years. Plus, I was tired of getting 'frown headaches' every time I went out into the sun.  Injecting hundreds of dollars into my forehead was not a decision that came lightly.  I'm not struggling financially, but this was definitely a splurge-and-let's-see-what-happens kind of a purchase.  I did my research, weighed the potential risks, and got a referral to a local and quite reputable dermatologist used by a co-worker. I entered with reasonable expectations:  I knew what the price range should be and was prepared to spend anywhere from $300 - $400, and I understood that everyone has different results and sometimes they're not so great (droopy eyelid, for instance). I was also aware that this treatment would last only about 4 months, give or take a month -- or, at least, that's what all the literature, the Botox website and the doctor told me. It is now exactly two months and one week since my injections and I have a ridged forehead again.  The results at first were very satisfying and pretty much what I expected - I still had eyebrow movement, I could still frown slightly, but the center and most ridged area was smooth and immobile.  But after about a month I could move the center again. Now, two months later I'm nearly back where I started. I went back to the doc today to discuss my options and was given platitudes: You have unusually strong forehead muscles...everyone metabolizes the serum differently....your muscles will weaken over time (and repeated injections) and the effects will then last longer.  Oh yeah?  Then how about a freebie 'booster' shot since you told me this would last four months?!?  (Did I mention that I also found out today that I was being charged for the initial consultation, during which no treatments were applied?!) This wouldn't have left such a bad taste in my mouth if he'd simply warned me that my strong forehead muscles - which he commented on during the original injection procedure - could mean that the effects might not last the average four months.  Or even three!  Very disappointing, and I feel very much misled by the Botox literature and him.  So, word to the wise:  don't necessarily believe the Botox literature or even your own doc when they tell you this treatment will last around four months.  And weigh that possibility carefully before you plop down hundreds of dollars on something that may be as fleeting as a summer vacation....