**Core Concept**
Burn wounds extending into the superficial epidermis without involving the dermis are characterized by limited damage to the nerve endings and blood vessels. This type of injury is typically associated with minor burns that do not penetrate through the entire epidermal layer.

**Why the Correct Answer is Right**
The correct answer, anaesthesia at the site of burns, is incorrect because superficial epidermal burns do not typically cause nerve damage that leads to anaesthesia. The presence of nerve endings in the epidermis allows for the sensation of pain, which is why superficial burns are often painful. This is in contrast to deeper burns that involve the dermis, which can cause nerve damage and result in anaesthesia or decreased sensation.

**Why Each Wrong Option is Incorrect**
**Option A:** Healing of the wound spontaneously without scar formation is incorrect because even superficial burns can still cause some degree of scarring due to the inflammatory response and the activation of the body's healing mechanisms.

**Option C:** Blister formation is incorrect because superficial epidermal burns are typically characterized by the formation of blisters due to the accumulation of fluid between the epidermis and dermis. However, this option is not the best answer because blister formation is still possible in superficial burns.

**Option D:** Painful is incorrect because superficial epidermal burns are indeed painful due to the presence of nerve endings in the epidermis.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the depth of a burn is not always immediately apparent and can only be confirmed after the burn has been debrided and examined. This is why accurate assessment and management of burn wounds are critical to prevent complications and promote optimal healing.

**✓ Correct Answer: B. Anaesthesia at the site of burns**