First of all, you should go back to you doctor and he should help you with your hyperpigmentation.
1. Is it correct that dermastamping is better than dermarolling, In general, no. Each alone or their combination has its role for specific cases. Dermastamping is more targeted and more intensive and is very effective for all types of scars and wrinkles. Dermarolling is more suitable for example for large areas of sun damaged, lost elasticity skin.
Basically, all effective skin rejuvenation methods are based on slightly damaging the skin. You can read about it here:
https://http://owndoc.com/dermarolling/how-dermarolling-works/ The only reservations I have is using a 2 mm dermaroller on (thin) facial skin. Concerning the face, I basically only recommend this size for men with serious facial scars.
2. is needling on deeper scars a bad thing in itself, or did him performing that procedure badly lead to this redness?,
No, it is not a bad approach at all. Needling indented scars, whether deep or shallow very often fills them up or partially fills them up.
Unfortunately, in some rare cases, in individuals very prone to get hyperpigmentation, the skin reacts to needling by producing more pigment melanin (melanin is normally present in the skin). Individuals prone to hyperpigmentation can get hyperpigmentation even after very small skin "disruptions" for example a bug bite.
3. most importantly what products do you have that can get rid of these apparently permanent red / discoloured patches of skin / circles around my 3 scars? Please help! Thank you in advance.
The only product that we sell which could help is Tretinoin.
I will paste here my reply from another forum thread concerning pigmentations (in your case, it is probably melanin):
Sometimes, it is residual inflammation. Try this: buy a non steroidal anti-inflammatory such as Nurofen rapid capsules (it contains liquid ibuprofen). For sale in pharmacies (OTC). Prick the capsule and apply some of it at least twice a day on the pigmentation. It may sting.
And sometimes it is overproduced melanin pigment. Melanin is skin pigment that is normally present in the skin but unfortunately the skin often reacts to skin injuries by overproducing the pigment. Even very small skin disturbances, like a bug bite, can in some individuals result in the overproduction of melanin in that spot. What helps then is Tyrosinase inhibitors such as hydroquinone. They inhibit the enzyme that converts tyrosine to melanin. They do not remove existing melanin, they only prevent formation of excessive melanin in the future so you have to use them long term.
It can also be a combination of residual inflammation and melanin overproduction.
What sometimes helps (in both cases) are products that speed up the turnover of the skin - microneedling, acid peels, Tretinoin cream etc.