Totally understandable

Other Potential Serious Side Effects
Rexulti may cause other serious side effects, so it is important to discuss your full medical history with your healthcare provider:
Metabolic changes, including high blood sugar (hyperglycemia) and diabetes
Uncontrolled body movements (tardive dyskinesia)
Neuroleptic Malignant Syndrome (NMS), a potentially fatal condition
Low white blood cell count
Difficulty swallowing

Rexulti (brexpiprazole) is not FDA-approved for treating autism spectrum disorder (ASD). The U.S. Food and Drug Administration (FDA) has, however, requested studies into its use for irritability associated with autism in children and adolescents, though a recent Phase 3 trial did not show a significant effect compared to a placebo.
Current Status of Rexulti for Autism
Not an FDA-Approved Treatment for Autism: Rexulti is currently approved for the treatment of schizophrenia in adults and adolescents (ages 13 and older), as an add-on therapy for major depressive disorder in adults, and for agitation associated with dementia due to Alzheimer's disease. It does not have an official indication for any symptom of autism.
Ongoing Research: The manufacturer has investigated Rexulti's potential to treat irritability (including aggression and self-injury) in children and adolescents with ASD through clinical trials. The initial results from a Phase 3 trial indicated no significant efficacy versus placebo for this use.
Off-Label Use: It is likely that other antipsychotics, including brexpiprazole (Rexulti), may be used "off-label" for severe behavioral issues in people with autism if FDA-approved options are insufficient.
FDA-Approved Medications for Autism-Related Irritability
Currently, only two medications are FDA-approved specifically for the management of irritability associated with autistic disorder in pediatric patients:
Risperidone (Risperdal): Approved for children aged 5 to 16 years.
Aripiprazole (Abilify): Approved for children aged 6 to 17 years.

I just read that Rexulti may have fewer side effects than Abilify. The only downside is that it is only available in the brand-name form, I believe.

Try healthunlocked.com plenty of people/patients on there with real live experience of medications but remember not everyone reacts the same way to certain medication. They should be able to tell you something though

I’ve been taking Rexulti and so far it’s okay, but I don’t like the side effects. I take it at night with risperidone.