Best Non-surgical Treatment to Lift Skin and Build Collagen?

You can do plenty of things to help you with your expression lines, but first of all, we must talk about why these lines appear; one of these reasons is sun exposure that can gradually cause loss of collagen and elasticity; constant facial expressions is another reason. I recommend drinking 1lt of water daily, a good sunscreen above 30, regular facials with microdermabrasion, microneedling with platelets rich plasma, and a combination of CO2 laser and erbium laser. I suggest that your forehead lines get botulinum toxin like Botox or Dysport to relax your muscles, giving you a more relaxed look. For your lower face and bars around the mouth, I suggest dermal fillers such as Restylane to fill in each line and hydrate the skin from giving you that natural refreshed look.

Dear dee4now,
Thank you for your question. To anwer this, lets first understand why do we have saggy skin. It is due to 2 main reasons.
1. Biological ageing – Gradual loss of collagen, elastin, hyaluronic acid in skin, bone loss and soft tissue loss
2. Photo-ageing – Sun exposure leads to free radical damage of skin collagen, elastin, Hyaluronic acid
Here are your non surgical options.
Microbotox + FillersLifting with ThreadliftMaintainence with energy based devices – RF, HIFU
Micro-toxin is a special technique that helps to tighten and firm the upper layers of your skin.
Fillers help to revolumise, hence restoring volume to your alar groove.
Threadlifts serve to lift, reposition your saggy skin causing the nasolabial folds.
HIFU and RF stimulate fibroblasts to induce neo-collagenesis.
All the above treatments promote collagen growth, hence further enhancing the skin firming and tightening result. This improves skin quality and dynamism. 
For optimum results in patients with a fair degree of sagginess, I advocate combining all 3 steps. step 1 and 2 to fill and lift your face. This is followed by maintainence with step 3, 3 months later. 
I hope this helps you.