How long does the effect of the diet injection last?

Overall, I've lost a little weight, but strangely, the fat on my inner thighs and sides just won't go away. It's so upsetting because my clothes just don't fit well whenever I wear them. I wonder if I should exercise harder, but since I've heard it's hard to lose weight in specific areas, I've been looking into diet injections lately.

I've heard people around me say their body lines improved a lot after getting diet injections, so I'm curious if they are really effective for areas where weight just won't budge through exercise!

I am also curious about how long the effects last once the body lines are defined with injections like this. I want to know if I need to strictly manage my diet during the duration to maintain the results without yo-yoing, and I would like to hear realistic reviews from those who have actually tried it!