How to change skin colour and facial appearance of a played sim

When my sim give birth of a child ,and when the child grow up the skin colour and facial look remains default as game decide.but if i want to change skin colour of the child or eyes/ears/lips etc,how to change this?i tried Modify in CAS but it only lets me change hair and cloths.so please tell me how i can change looks,hair,eye and also need to know how to change traits of a played sim.aspirations can be changed.but how to change traits and relationships of played sims ?

There is a mod at Mod The Sims which is called full edit mode.
Tmex-AlwaysFullEditMode , it is a script mod, should be extracted and placed directly into mods folder. No other folders. I had it in another folder, it did not work. So I re-read instructions, now it is directly there and it works perfectly. Changed my Vampire sims and made them truly beautiful, nice bodies, everything. Changed skintone, eyes, hair, body,  So it works. Also for this version of sims 4 as well as the one from ZL Origin. I also changed the Complete Landgraab Family and their aspirations. Worked well. (From Timex there is also a always free build mod, which works like a charm. Will now attempt to modernize the Landgraab family home. )
Try it, good luck!