How do I know if I developed antibodies for Botox? Had second Botox in 3 months and top up again and it didn't work. Thoughts?

Based on your description it sounds more likely that you were dosed incorrectly for your treatments.  Botox results fade gradually over three to four months with proper dosing.  I encourage you to visit an experienced injector for your treatment with proven results.

Hello, thank you for your inquiry. In most cases such as this but not limited to all, the problem may be that most of us are a little different with how our body reacts, heals, takes in and it probably requires a slightly different injection pattern. 

Usually antibodies to botox occur after long term use of the product.  Since you are  fairly new to botox the most likely cause of this is placement and/or dosing of the botox.  If the botox it is being diluted too much, it is not properly stored or  the dose is too low for the individual it may not give you the results you desire or it will wear  off sooner than expected. You should discuss your concerns with your injector who should be able to make adjustments.