Sorry about the wait! Basically, blaster bolts may or may not cauterize the wound they make. There will certainly be burning, but they can still bleed. Due to the physics of a blaster bolt, blunt force injuries can also occur. (I discuss this in a bit more detail here and here). Most often, however, the wound is largely cauterized by the heat of the bolt. As a result, they are very difficult to treat without the regenerative properties of bacta, and thus the default treatment is application of a bacta bandage or, if the injury is serious enough, submersion in a bacta tank. The bandages must be changed regularly, and the patient may need surgery if the bolt has hit and burnt any organs, but if they can survive long enough to get treatment they often make a full recovery.
Hope that helps!
~ Jacen