You just lose one from what you'd normally gain. At level 1, you would normally have 8 max HP, now you get 7. At level two, you would usually add 6 to your max, instead you'll add 5, so on and so forth.
I did want to address one other thing. You've been going weeks with no response on these boards. Obviously, your time is your own, and life happens, but it isn't fair to your fellow players if we can't count on you to respond more than once or twice a month.
I don't mean this as a criticism, just something to keep in mind for the future. Before, the only person you delayed by not sticking around was yourself, now it is potentially everyone else involved.
Edited: daishain on 4th Apr, 2018 - 11:05pm
You still start out at Max hit points the -1 does not start until you level up. So each level you can roll for new HP and take one away or you can take half of your hit die. Other would get half +1 but you will not due to the -1.
I do hope that you stay active as there are not many currently playing.
Okay, Avan has levelled up overnight. Changes:
7 Skills: Concentration +1, Handle Animal +2, Ride +3, Spellcraft +1
+1 Hit die (Rolled)
+1 BAB, Fort, Ref, Will
Wild shape (+1/day)
+ Feat: Natural Spell
Jackal:
+2 hit dice
[+1 BAB, Fort, Ref, Will,
2 Skills: Move Silently +2
+ 1 Feat: Power Attack]
+2 Natural Armor
+1 Strength and Dexterity
+1 Bonus Trick
+ Evasion
Rolling for HP:.