There are several effective ways to help fade dark spots on the face resulting from old pimples. Here are a few methods you can try:

1. Use of Skincare Products: Look for products containing ingredients like retinol, vitamin C, niacinamide, or hydroquinone as they are known to help fade dark spots over time.

2. Exfoliation: Regular exfoliation can help slough off dead skin cells and promote new skin cell turnover, which may help fade dark spots.

3. Sun Protection: Use sunscreen daily to prevent dark spots from darkening further. Sun exposure can worsen hyperpigmentation.

4. Professional Treatments: Options such as chemical peels, microdermabrasion, laser therapy, or intense pulsed light (IPL) treatments can be effective in reducing the appearance of dark spots, but consult a dermatologist for these treatments.

5. Home Remedies: Some natural remedies like applying lemon juice, aloe vera, or honey to the dark spots may also help in fading them, but these methods may not be as effective as clinically proven treatments.

It’s essential to test products on a small patch of skin first to ensure you don’t have any adverse reactions. It’s recommended to consult a dermatologist for personalized advice and treatment options based on your skin type and the severity of the dark spots.