Dark Spots Treatment Hydroquinone 4%?

   Yes.  Unfortunately, after stopping HQ it is not surprising if the dark spots return, particularly if you are exposed to any sunlight.  Obviously, sun avoidance and sunscreens are important to prevent the recurrence of the dark spots.  Light to medium chemical peels or lasers would also be beneficial.

I would start with an intense skin rejuvenation protocol for age spots that includes fractional laser, Covalent chemical peels, and daily skin brightening creams to improve your skin’s complexion. Laser therapy must be combined with a proper skin regimen to enhance and maintain youthful results.
The following skincare products for dark age spots: Melarase
MelaClenz Brightening CleanserMelarase AM: Day-time skin lightener with SPF 30Melarase PM: Night-time skin lightenerMelapads: Daily Exfoliating PadsReplenish Retinoid Cream: Exfoliating and skin-stimulating night creamBest, 
Dr. Karamanoukian
Realself100 Surgeon

Treatment of hyperpigmented patches, particularly in ethnic skin requires strict daily sun protection, topical C product in the morning, combination of hydroquinone and prescription-strength retinoid may be appropriate for oily prone skin. For most patients with sensitive skin however, topical hydroquinone may not be easily tolerated and have to be preceded by light moisturizer 30 minutes prior. One may consider non-hydroquinone containing bleaching cream with active ingredients of arbutin, kojic acid, embilica, etc. As a last resort, we may offer Nd:Yag lasers such as GenesisPlus laser or Spectra laser.