Should PRP injections burn horrible while going into skin? Shouldn’t substantance be yellow not red?

Hello tnrfazio,
PRP injections should not be painful where you can't tolerate the injections. On a scale of 0-10- zero is no pain and 10 the worst pain ever, you might experience a 2-3 pain discomfort. The skin should be numbed with a cream-and then cleansed off prior to micro-needling and injection. If they wait too long  after the application of the numbing cream it will loose its effectiveness and you can experience  discomfort. Of they might not be using a strong enough numbing cream. BTL is one of the best.
PRP can be Red or what we call Pure PRP is yellow (lay term), depending on the centrifuge and program you use. Both are effective.
The injections and or micro needling should not burn but if they cleanse the skin just prior to injection with alcohol (standard protocol) there might be some burning..my clients have never complaint of a burning sensation.
Bruising and swelling comes as part of the treatment. Especially if the PRP is being injected. Remember we are injecting PRP into the dermis, thus the swelling and you are receiving 30-60 injections (approximately depending what area you are having done.) so bruising is expected.
Results from PRP or just microneedling (3 treatments a month apart is recommended) will usually be visible 1-3 months for micro needling and 6-8 months for PRP (works deep in the dermis to stimulate collagen and elastin from the stem cells and growth factors in the PRP-it's a process-

I'm assuming your skin was numbed and it was the injections that burned. The burn is generally caused by the type of anticoagulant used. 
Whether or not I use that type of anticoagulant, I generally add a bit of sodium bicarbonate to the PRP to neutralize the Ph. For some patients which are hypersensitive, I will also add a touch of preservative free lidocaine. 
There's little reason to have discomfort.
A little blood in the PRP is OK, but not ideal for a facial procedure. Don't worry, I'm confident there won't be a problem. For some indications such as joints, I actually like some red cells in the PRP. 
Hope your outcome is wonderful!
Warmly,
Arbella Sarkis, MD 

Hello, The PRP tends to be an acidic solution so when injected it can cause inflammation and irritation. This is perfectly normal. Some centers add sodium bicarbonate to help neutralize the injection prior to receiving to help with discomfort. For the color, PRP should be a golden yellow color. The reddish tint represents RBCs present. This is not ideal but depending on the amount of RBCs it could still be an efficacious treatment.