The warmest side could probably be a few degrees higher (88*- keep under 90*) but I don't think that has anything to do with the "spots".
It appears to me to be some minor damage to the top of his head from rubbing on something- possibly he was too dry when he tried to shed & rubbed too hard? When he's in a shed cycle, it's best to raise the humidity to 65-75% to facilitate the removal of his old skin. Head rubs can also result from just climbing around- some snakes are more restless than others, or try to escape- so double-check cage enclosure for sharp or abrasive areas that he might have been injured by. If this is a tank with a screen top, consider how abrasive the screen top likely is- or if there's a wire mesh cover over a heat source, that too can be very abrasive. A rough screen top can be mitigated by lining the underside with non-abrasive nylon screen material, so he never contacts the rough stuff when he pushes or rubs against it.