RF treatments should be weekly for 4 treatments then monthly forever. no it cannot make the skin sag more, but should be combined with morpheus every 2 months, dermarolling weekly (see emeragecosmetics MTS roller with ANTEAGEMD ampules). threads are a yearly treatments and thermage/ultherapy every 6 months.
As we age the skin sags there is nothing you can do that but try preventative energy-based or thread-based treatments or get a neck/facelift earlier in the aging process. There are numerous options and some can be used in combination to get best outcomes but you need a consultation with an expert.
Options include for skin tightening : 1. thermage radiofrequency to heat skin and tighten it over time and prevent the aging process 2. ultherapy highintensity ultrasound to contract muscle and tighten the face and neck and prevent the aging process 3. PDO nova threads or instalift threads for immediate lifting without surgery and long term collagen production 4. sculptra injections for collagen production to areas of the face and neck with crepe skin or early sagging 5. btl exilis ultra, venus legacy, thermi250 , or inmode forma/contoura for constant collagen stimulation monthly with facials 6. facelift/necklift with fat grafting/fillers if you need a big improvement 7. ThermiRF or J plasma /Renuvion or Inmode FaceTite internal heating and tightening to long term internal heating and tighting with or without surgery 8. Platysmaplasty to tighten the muscles of the neck long term and create contour 9. Facial implants or fillers to contour the jawline and chin to improve the apperance of the nec k 10. Fractora/Morphenus8 or Intensif microneedling RF for improve superficial tightening, neck and chest wrinkling and crepe skin You need to see an expert in facial sculpting and age prevention. Best, Dr. Emer.