10 days ago I got Botox in my chin and it hit the DLI muscle. My lip drooped and can’t smile. Should I get Botox on opp side?

Thanks for the question and I am very sorry to hear that this has happened to you.
DLI is a lip depressor and evertor which means it pulls the lip down and rolls outwards during expression but it also has a resting “tone” which maintains the posture of your mouth at rest. 
When a toxin weakens or paralyses DLI, your lip will tend to sit higher and also roll inwards on the affected side. There is nothing that can be done for this side except to wait. You can have some toxin to the DLI on the other side. This will give you better facial symmetry while waiting for the toxin to wear off but it will also cause your lower lip to retract slightly. This will give an appearance of a smaller lower lip, you will show less of your lower teeth when you smile and you are more likely to catch your lip between your teeth which can be very annoying. 
I certainly would not try and treat this problem with additional filler.
Good luck!
Dr Chris Macdonald
CRM Aesthetics

Botox to the opposite DLI will adjust the smile so that is more even. Fillers will not help the problem as it is caused by inadvertent relaxation of a muscle that was not the intended recipient of the initial Botox. If you decide to have Botox in your chin in the future, the injector should keep the dose low, dilution of botox concentrated, and stay very medial and inferior on the chin with the injection to avoid hitting the DLI. If you do nothing, the Botox will wear off of course and your smile will return to normal. Best, Dr. Tkatch