Keloid, hypertrophic, acne...there are so many types of scars, and each of them affect us in different ways. I personally think a scar is beautiful ; it's a message that reads I've been through this and I'm still here.
That's not to say they make us feel 100% confident. My mum has a 7 inch scar across her stomach from a malignant melanoma. Again, it reads 'i kicked cancer's ass and I'm still going strong', but I've been with her through the bikini shopping and strolls on the beach (not in Britain unfortunately!) and know how self conscious she has felt.
The answer? First and foremost, MASSAGE, MASSAGE, MASSAGE. There are thousands of fancy creams and oils out there, but in my opinion a wee dab (yes, I am Scottish. Can you tell? ) of good old vaseline is the boss. MASSAGE the healing scar 4-5 times a day, or as much as you can with your chosen cream/oil and reap the rewards. This gives your skin a bit of a wake up call - it'll begin to break down old fibrous tissue and stimulate new collagen production.
If your scar is still sensitive to the touch, just be gentle and persevere with the massage, it will prevent the skin scarring too tightly and create a smoother, neater mark.
For makeup obviously concealer is a must. Use an oil free formula and stick to matte products - shine is only going to draw attention to the area. Match the colour to the area around the scar and not the line of the old wound itself. This rule can vary but is a good default.
For acne/pitted scarring your best friend is a cheap makeup sponge - the ones that look like wedges of cheese, cheap and cheerful! Don't fork out for these as they are honestly not worth it. Take one in hand and tear it (with your hands not scissors!) down the middle. You want to have two ragged wedges, the Middle section should be covered in tiny peaks and troughs. Use a cream foundation in your skin tone and use the ragged side to stipple this all over the face. The little points and grooves help to drive the products into the skin thus creating the right amount of in the indents of the skin. Finish with a matte powder and you're good to go!
I hope this helps! There is A LOT more on scarring that I could divulge but I don't want to overwhelm anyone, or worse - bore you!
Remember, any scar tells a story - be proud!